rust-postgres/src/lib.rs

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//! Rust-Postgres is a pure-Rust frontend for the popular PostgreSQL database. It
//! exposes a high level interface in the vein of JDBC or Go's `database/sql`
//! package.
//!
//! ```rust,no_run
//! extern crate postgres;
//! extern crate time;
//!
//! use time::Timespec;
//!
//! use postgres::{PostgresConnection, NoSsl};
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//!
//! struct Person {
//! id: i32,
//! name: String,
//! time_created: Timespec,
//! data: Option<Vec<u8>>
//! }
//!
//! fn main() {
//! let conn = PostgresConnection::connect("postgresql://postgres@localhost",
//! &NoSsl).unwrap();
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//!
//! conn.execute("CREATE TABLE person (
//! id SERIAL PRIMARY KEY,
//! name VARCHAR NOT NULL,
//! time_created TIMESTAMP NOT NULL,
//! data BYTEA
//! )", []).unwrap();
//! let me = Person {
//! id: 0,
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//! name: "Steven".to_string(),
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//! time_created: time::get_time(),
//! data: None
//! };
//! conn.execute("INSERT INTO person (name, time_created, data)
//! VALUES ($1, $2, $3)",
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//! [&me.name, &me.time_created, &me.data]).unwrap();
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//!
//! let stmt = conn.prepare("SELECT id, name, time_created, data FROM person")
//! .unwrap();
//! for row in stmt.query([]).unwrap() {
//! let person = Person {
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//! id: row.get(0u),
//! name: row.get(1u),
//! time_created: row.get(2u),
//! data: row.get(3u)
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//! };
//! println!("Found person {}", person.name);
//! }
//! }
//! ```
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#![doc(html_root_url="http://www.rust-ci.org/sfackler/rust-postgres/doc")]
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#![feature(macro_rules, struct_variant, phase, unsafe_destructor)]
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#![warn(missing_doc)]
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extern crate collections;
extern crate openssl;
extern crate serialize;
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extern crate time;
extern crate phf;
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#[phase(plugin)]
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extern crate phf_mac;
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extern crate url;
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#[phase(plugin, link)]
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extern crate log;
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use collections::{Deque, RingBuf};
use url::{UserInfo, Url};
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use openssl::crypto::hash::{MD5, Hasher};
use openssl::ssl::SslContext;
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use serialize::hex::ToHex;
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use std::cell::{Cell, RefCell};
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use std::collections::HashMap;
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use std::from_str::FromStr;
use std::io::{BufferedStream, IoResult};
use std::io::net::ip::Port;
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use std::mem;
use std::fmt;
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use error::{InvalidUrl,
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MissingPassword,
MissingUser,
PgConnectDbError,
PgConnectStreamError,
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PgConnectBadResponse,
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PgDbError,
PgInvalidColumn,
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PgStreamDesynchronized,
PgStreamError,
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PgWrongParamCount,
PostgresConnectError,
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PostgresDbError,
PostgresError,
UnsupportedAuthentication,
PgWrongConnection,
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PgWrongTransaction,
PgBadResponse};
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use io::{MaybeSslStream, InternalStream};
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use message::{AuthenticationCleartextPassword,
AuthenticationGSS,
AuthenticationKerberosV5,
AuthenticationMD5Password,
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AuthenticationOk,
AuthenticationSCMCredential,
AuthenticationSSPI,
BackendKeyData,
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BackendMessage,
BindComplete,
CommandComplete,
DataRow,
EmptyQueryResponse,
ErrorResponse,
NoData,
NoticeResponse,
NotificationResponse,
ParameterDescription,
ParameterStatus,
ParseComplete,
PortalSuspended,
ReadyForQuery,
RowDescription,
RowDescriptionEntry};
use message::{Bind,
CancelRequest,
Close,
Describe,
Execute,
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FrontendMessage,
Parse,
PasswordMessage,
Query,
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StartupMessage,
Sync,
Terminate};
use message::{WriteMessage, ReadMessage};
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use types::{Oid, PostgresType, ToSql, FromSql, PgUnknownType, Binary};
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#[macro_escape]
mod macros;
pub mod error;
mod io;
pub mod pool;
mod message;
pub mod types;
static CANARY: u32 = 0xdeadbeef;
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/// A typedef of the result returned by many methods.
pub type PostgresResult<T> = Result<T, PostgresError>;
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/// Specifies the target server to connect to.
#[deriving(Clone)]
pub enum PostgresConnectTarget {
/// Connect via TCP to the specified host.
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TargetTcp(String),
/// Connect via a Unix domain socket in the specified directory.
TargetUnix(Path)
}
/// Authentication information
#[deriving(Clone)]
pub struct PostgresUserInfo {
/// The username
pub user: String,
/// An optional password
pub password: Option<String>,
}
/// Information necessary to open a new connection to a Postgres server.
#[deriving(Clone)]
pub struct PostgresConnectParams {
/// The target server
pub target: PostgresConnectTarget,
/// The target port.
///
/// Defaults to 5432 if not specified.
pub port: Option<Port>,
/// The user to login as.
///
/// `PostgresConnection::connect` requires a user but `cancel_query` does
/// not.
pub user: Option<PostgresUserInfo>,
/// The database to connect to. Defaults the value of `user`.
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pub database: Option<String>,
/// Runtime parameters to be passed to the Postgres backend.
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pub options: Vec<(String, String)>,
}
/// A trait implemented by types that can be converted into a
/// `PostgresConnectParams`.
pub trait IntoConnectParams {
/// Converts the value of `self` into a `PostgresConnectParams`.
fn into_connect_params(self) -> Result<PostgresConnectParams, PostgresConnectError>;
}
impl IntoConnectParams for PostgresConnectParams {
fn into_connect_params(self) -> Result<PostgresConnectParams, PostgresConnectError> {
Ok(self)
}
}
impl<'a> IntoConnectParams for &'a str {
fn into_connect_params(self) -> Result<PostgresConnectParams, PostgresConnectError> {
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match Url::parse(self) {
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Ok(url) => url.into_connect_params(),
Err(err) => return Err(InvalidUrl(err)),
}
}
}
impl IntoConnectParams for Url {
fn into_connect_params(self) -> Result<PostgresConnectParams, PostgresConnectError> {
let Url {
host,
port,
user,
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path: url::Path { path, query: options, .. },
..
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} = self;
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let maybe_path = match url::decode_component(host.as_slice()) {
Ok(path) => path,
Err(err) => return Err(InvalidUrl(err)),
};
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let target = if maybe_path.as_slice().starts_with("/") {
TargetUnix(Path::new(maybe_path))
} else {
TargetTcp(host)
};
let user = match user {
Some(UserInfo { user, pass }) =>
Some(PostgresUserInfo { user: user, password: pass }),
None => None,
};
let database = if !path.is_empty() {
// path contains the leading /
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let (_, path) = path.as_slice().slice_shift_char();
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Some(path.to_string())
} else {
None
};
Ok(PostgresConnectParams {
target: target,
port: port,
user: user,
database: database,
options: options,
})
}
}
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/// Trait for types that can handle Postgres notice messages
pub trait PostgresNoticeHandler {
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/// Handle a Postgres notice message
fn handle(&mut self, notice: PostgresDbError);
}
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/// A notice handler which logs at the `info` level.
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///
/// This is the default handler used by a `PostgresConnection`.
pub struct DefaultNoticeHandler;
impl PostgresNoticeHandler for DefaultNoticeHandler {
fn handle(&mut self, notice: PostgresDbError) {
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info!("{}: {}", notice.severity, notice.message);
}
}
/// An asynchronous notification
pub struct PostgresNotification {
/// The process ID of the notifying backend process
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pub pid: u32,
/// The name of the channel that the notify has been raised on
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pub channel: String,
/// The "payload" string passed from the notifying process
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pub payload: String,
}
/// An iterator over asynchronous notifications
pub struct PostgresNotifications<'conn> {
conn: &'conn PostgresConnection
}
impl<'conn> Iterator<PostgresNotification> for PostgresNotifications<'conn> {
/// Returns the oldest pending notification or `None` if there are none.
///
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/// ## Note
///
/// `next` may return `Some` notification after returning `None` if a new
/// notification was received.
fn next(&mut self) -> Option<PostgresNotification> {
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self.conn.conn.borrow_mut().notifications.pop_front()
}
}
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/// Contains information necessary to cancel queries for a session
pub struct PostgresCancelData {
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/// The process ID of the session
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pub process_id: u32,
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/// The secret key for the session
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pub secret_key: u32,
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}
/// Attempts to cancel an in-progress query.
///
/// The backend provides no information about whether a cancellation attempt
/// was successful or not. An error will only be returned if the driver was
/// unable to connect to the database.
///
/// A `PostgresCancelData` object can be created via
/// `PostgresConnection::cancel_data`. The object can cancel any query made on
/// that connection.
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///
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/// Only the host and port of the connetion info are used. See
/// `PostgresConnection::connect` for details of the `params` argument.
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///
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/// ## Example
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///
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/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
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/// # let url = "";
/// let conn = PostgresConnection::connect(url, &NoSsl).unwrap();
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/// let cancel_data = conn.cancel_data();
/// spawn(proc() {
/// conn.execute("SOME EXPENSIVE QUERY", []).unwrap();
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/// });
/// # let _ =
/// postgres::cancel_query(url, &NoSsl, cancel_data);
/// ```
pub fn cancel_query<T>(params: T, ssl: &SslMode, data: PostgresCancelData)
-> Result<(), PostgresConnectError> where T: IntoConnectParams {
let params = try!(params.into_connect_params());
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let mut socket = match io::initialize_stream(&params, ssl) {
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Ok(socket) => socket,
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Err(err) => return Err(err)
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};
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try_pg_conn!(socket.write_message(&CancelRequest {
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code: message::CANCEL_CODE,
process_id: data.process_id,
secret_key: data.secret_key
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}));
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try_pg_conn!(socket.flush());
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Ok(())
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}
struct InnerPostgresConnection {
stream: BufferedStream<MaybeSslStream<InternalStream>>,
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next_stmt_id: uint,
notice_handler: Box<PostgresNoticeHandler+Send>,
notifications: RingBuf<PostgresNotification>,
cancel_data: PostgresCancelData,
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unknown_types: HashMap<Oid, String>,
desynchronized: bool,
finished: bool,
trans_depth: u32,
canary: u32,
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}
impl Drop for InnerPostgresConnection {
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fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
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}
}
impl InnerPostgresConnection {
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fn connect<T>(params: T, ssl: &SslMode)
-> Result<InnerPostgresConnection, PostgresConnectError>
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where T: IntoConnectParams {
let params = try!(params.into_connect_params());
let stream = try!(io::initialize_stream(&params, ssl));
let PostgresConnectParams {
user,
database,
mut options,
..
} = params;
let user = match user {
Some(user) => user,
None => return Err(MissingUser),
};
let mut conn = InnerPostgresConnection {
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stream: BufferedStream::new(stream),
next_stmt_id: 0,
notice_handler: box DefaultNoticeHandler,
notifications: RingBuf::new(),
cancel_data: PostgresCancelData { process_id: 0, secret_key: 0 },
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unknown_types: HashMap::new(),
desynchronized: false,
finished: false,
trans_depth: 0,
canary: CANARY,
};
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options.push(("client_encoding".to_string(), "UTF8".to_string()));
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// Postgres uses the value of TimeZone as the time zone for TIMESTAMP
// WITH TIME ZONE values. Timespec converts to GMT internally.
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options.push(("TimeZone".to_string(), "GMT".to_string()));
// We have to clone here since we need the user again for auth
options.push(("user".to_string(), user.user.clone()));
match database {
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Some(database) => options.push(("database".to_string(), database)),
None => {}
}
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try_pg_conn!(conn.write_messages([StartupMessage {
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version: message::PROTOCOL_VERSION,
parameters: options.as_slice()
}]));
try!(conn.handle_auth(user));
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loop {
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match try_pg_conn!(conn.read_message()) {
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BackendKeyData { process_id, secret_key } => {
conn.cancel_data.process_id = process_id;
conn.cancel_data.secret_key = secret_key;
}
ReadyForQuery { .. } => break,
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ErrorResponse { fields } =>
return Err(PgConnectDbError(PostgresDbError::new(fields))),
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_ => return Err(PgConnectBadResponse),
}
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}
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Ok(conn)
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}
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fn write_messages(&mut self, messages: &[FrontendMessage]) -> IoResult<()> {
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debug_assert!(!self.desynchronized);
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for message in messages.iter() {
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try_desync!(self, self.stream.write_message(message));
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}
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Ok(try_desync!(self, self.stream.flush()))
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}
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fn read_message(&mut self) -> IoResult<BackendMessage> {
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debug_assert!(!self.desynchronized);
loop {
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match try_desync!(self, self.stream.read_message()) {
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NoticeResponse { fields } => {
self.notice_handler.handle(PostgresDbError::new(fields))
}
NotificationResponse { pid, channel, payload } => {
self.notifications.push(PostgresNotification {
pid: pid,
channel: channel,
payload: payload
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})
}
ParameterStatus { parameter, value } => {
debug!("Parameter {} = {}", parameter, value)
}
val => return Ok(val)
}
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}
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}
fn handle_auth(&mut self, user: PostgresUserInfo) -> Result<(), PostgresConnectError> {
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match try_pg_conn!(self.read_message()) {
AuthenticationOk => return Ok(()),
AuthenticationCleartextPassword => {
let pass = match user.password {
Some(pass) => pass,
None => return Err(MissingPassword)
};
try_pg_conn!(self.write_messages([PasswordMessage {
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password: pass.as_slice(),
}]));
}
AuthenticationMD5Password { salt } => {
let pass = match user.password {
Some(pass) => pass,
None => return Err(MissingPassword)
};
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let hasher = Hasher::new(MD5);
hasher.update(pass.as_bytes());
hasher.update(user.user.as_bytes());
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let output = hasher.final().as_slice().to_hex();
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let hasher = Hasher::new(MD5);
hasher.update(output.as_bytes());
hasher.update(salt);
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let output = format!("md5{}",
hasher.final().as_slice().to_hex());
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try_pg_conn!(self.write_messages([PasswordMessage {
password: output.as_slice()
}]));
}
AuthenticationKerberosV5
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| AuthenticationSCMCredential
| AuthenticationGSS
| AuthenticationSSPI => return Err(UnsupportedAuthentication),
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ErrorResponse { fields } => return Err(PgConnectDbError(PostgresDbError::new(fields))),
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_ => {
self.desynchronized = true;
return Err(PgConnectBadResponse);
}
}
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match try_pg_conn!(self.read_message()) {
AuthenticationOk => Ok(()),
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ErrorResponse { fields } => Err(PgConnectDbError(PostgresDbError::new(fields))),
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_ => {
self.desynchronized = true;
return Err(PgConnectBadResponse);
}
}
}
fn set_notice_handler(&mut self, handler: Box<PostgresNoticeHandler+Send>)
-> Box<PostgresNoticeHandler+Send> {
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mem::replace(&mut self.notice_handler, handler)
}
fn prepare<'a>(&mut self, query: &str, conn: &'a PostgresConnection)
-> PostgresResult<PostgresStatement<'a>> {
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let stmt_name = format!("s{}", self.next_stmt_id);
self.next_stmt_id += 1;
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try_pg!(self.write_messages([
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Parse {
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name: stmt_name.as_slice(),
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query: query,
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param_types: []
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},
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Describe {
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variant: 'S' as u8,
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name: stmt_name.as_slice(),
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},
Sync]));
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match try_pg!(self.read_message()) {
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ParseComplete => {}
ErrorResponse { fields } => {
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try!(self.wait_for_ready());
return Err(PgDbError(PostgresDbError::new(fields)));
}
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_ => bad_response!(self),
}
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let mut param_types: Vec<PostgresType> = match try_pg!(self.read_message()) {
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ParameterDescription { types } => {
types.iter().map(|ty| PostgresType::from_oid(*ty)).collect()
}
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_ => bad_response!(self),
};
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let mut result_desc: Vec<ResultDescription> = match try_pg!(self.read_message()) {
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RowDescription { descriptions } => {
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descriptions.move_iter().map(|desc| {
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let RowDescriptionEntry { name, type_oid, .. } = desc;
ResultDescription {
name: name,
ty: PostgresType::from_oid(type_oid)
}
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}).collect()
}
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NoData => vec![],
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_ => bad_response!(self)
};
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try!(self.wait_for_ready());
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// now that the connection is ready again, get unknown type names
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try!(self.set_type_names(param_types.mut_iter()));
try!(self.set_type_names(result_desc.mut_iter().map(|d| &mut d.ty)));
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Ok(PostgresStatement {
conn: conn,
name: stmt_name,
param_types: param_types,
result_desc: result_desc,
next_portal_id: Cell::new(0),
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finished: false,
})
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}
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fn set_type_names<'a, I: Iterator<&'a mut PostgresType>>(&mut self, mut it: I)
-> PostgresResult<()> {
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for ty in it {
match *ty {
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PgUnknownType { oid, ref mut name } => *name = try!(self.get_type_name(oid)),
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_ => {}
}
}
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Ok(())
}
fn get_type_name(&mut self, oid: Oid) -> PostgresResult<String> {
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match self.unknown_types.find(&oid) {
Some(name) => return Ok(name.clone()),
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None => {}
}
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let name = try!(self.quick_query(format!("SELECT typname FROM pg_type \
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WHERE oid={}", oid).as_slice()))
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.move_iter().next().unwrap().move_iter().next().unwrap().unwrap();
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self.unknown_types.insert(oid, name.clone());
Ok(name)
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}
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fn is_desynchronized(&self) -> bool {
self.desynchronized
}
fn canary(&self) -> u32 {
self.canary
}
fn wait_for_ready(&mut self) -> PostgresResult<()> {
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match try_pg!(self.read_message()) {
ReadyForQuery { .. } => Ok(()),
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_ => bad_response!(self)
}
}
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fn quick_query(&mut self, query: &str) -> PostgresResult<Vec<Vec<Option<String>>>> {
check_desync!(self);
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try_pg!(self.write_messages([Query { query: query }]));
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let mut result = vec![];
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loop {
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match try_pg!(self.read_message()) {
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ReadyForQuery { .. } => break,
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DataRow { row } => {
result.push(row.move_iter().map(|opt| {
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opt.map(|b| String::from_utf8(b).unwrap())
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}).collect());
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}
ErrorResponse { fields } => {
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try!(self.wait_for_ready());
return Err(PgDbError(PostgresDbError::new(fields)));
}
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_ => {}
}
}
Ok(result)
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}
fn finish_inner(&mut self) -> PostgresResult<()> {
check_desync!(self);
self.canary = 0;
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try_pg!(self.write_messages([Terminate]));
Ok(())
}
}
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/// A connection to a Postgres database.
pub struct PostgresConnection {
conn: RefCell<InnerPostgresConnection>
}
impl PostgresConnection {
/// Creates a new connection to a Postgres database.
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///
/// Most applications can use a URL string in the normal format:
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///
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/// ```notrust
/// postgresql://user[:password]@host[:port][/database][?param1=val1[[&param2=val2]...]]
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/// ```
///
/// The password may be omitted if not required. The default Postgres port
/// (5432) is used if none is specified. The database name defaults to the
/// username if not specified.
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///
/// To connect to the server via Unix sockets, `host` should be set to the
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/// absolute path of the directory containing the socket file. Since `/` is
/// a reserved character in URLs, the path should be URL encoded. If the
/// path contains non-UTF 8 characters, a `PostgresConnectParams` struct
/// should be created manually and passed in. Note that Postgres does not
/// support SSL over Unix sockets.
///
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/// ## Examples
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///
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/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
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/// # let _ = || {
/// let url = "postgresql://postgres:hunter2@localhost:2994/foodb";
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/// let conn = try!(PostgresConnection::connect(url, &NoSsl));
/// # Ok(()) };
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/// ```
///
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/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
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/// # let _ = || {
/// let url = "postgresql://postgres@%2Frun%2Fpostgres";
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/// let conn = try!(PostgresConnection::connect(url, &NoSsl));
/// # Ok(()) };
/// ```
///
/// ```rust,no_run
/// # use postgres::{PostgresConnection, PostgresUserInfo, PostgresConnectParams, NoSsl, TargetUnix};
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/// # let _ = || {
/// # let some_crazy_path = Path::new("");
/// let params = PostgresConnectParams {
/// target: TargetUnix(some_crazy_path),
/// port: None,
/// user: Some(PostgresUserInfo {
/// user: "postgres".to_string(),
/// password: None
/// }),
/// database: None,
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/// options: vec![],
/// };
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/// let conn = try!(PostgresConnection::connect(params, &NoSsl));
/// # Ok(()) };
/// ```
pub fn connect<T>(params: T, ssl: &SslMode) -> Result<PostgresConnection, PostgresConnectError>
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where T: IntoConnectParams {
InnerPostgresConnection::connect(params, ssl).map(|conn| {
PostgresConnection { conn: RefCell::new(conn) }
})
}
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/// Sets the notice handler for the connection, returning the old handler.
pub fn set_notice_handler(&self, handler: Box<PostgresNoticeHandler+Send>)
-> Box<PostgresNoticeHandler+Send> {
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self.conn.borrow_mut().set_notice_handler(handler)
}
/// Returns an iterator over asynchronous notification messages.
///
/// Use the `LISTEN` command to register this connection for notifications.
pub fn notifications<'a>(&'a self) -> PostgresNotifications<'a> {
PostgresNotifications {
conn: self
}
}
/// Creates a new prepared statement.
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///
/// A statement may contain parameters, specified by `$n` where `n` is the
/// index of the parameter in the list provided at execution time,
/// 1-indexed.
///
/// The statement is associated with the connection that created it and may
/// not outlive that connection.
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///
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/// ## Example
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///
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/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
/// # let conn = PostgresConnection::connect("", &NoSsl).unwrap();
/// let maybe_stmt = conn.prepare("SELECT foo FROM bar WHERE baz = $1");
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/// let stmt = match maybe_stmt {
/// Ok(stmt) => stmt,
/// Err(err) => fail!("Error preparing statement: {}", err)
/// };
pub fn prepare<'a>(&'a self, query: &str) -> PostgresResult<PostgresStatement<'a>> {
let mut conn = self.conn.borrow_mut();
if conn.trans_depth != 0 {
return Err(PgWrongTransaction);
}
conn.prepare(query, self)
}
/// Begins a new transaction.
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///
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/// Returns a `PostgresTransaction` object which should be used instead of
/// the connection for the duration of the transaction. The transaction
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/// is active until the `PostgresTransaction` object falls out of scope.
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///
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/// ## Note
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/// A transaction will roll back by default. Use the `set_commit` method to
/// set the transaction to commit.
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///
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/// ## Example
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///
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/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
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/// # fn foo() -> Result<(), postgres::error::PostgresError> {
/// # let conn = PostgresConnection::connect("", &NoSsl).unwrap();
/// let trans = try!(conn.transaction());
/// try!(trans.execute("UPDATE foo SET bar = 10", []));
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/// // ...
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///
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/// trans.set_commit();
/// try!(trans.finish());
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/// # Ok(())
/// # }
/// ```
pub fn transaction<'a>(&'a self) -> PostgresResult<PostgresTransaction<'a>> {
check_desync!(self);
if self.conn.borrow().trans_depth != 0 {
return Err(PgWrongTransaction);
}
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try!(self.quick_query("BEGIN"));
self.conn.borrow_mut().trans_depth += 1;
Ok(PostgresTransaction {
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conn: self,
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commit: Cell::new(false),
depth: 1,
finished: false,
})
}
/// A convenience function for queries that are only run once.
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///
/// If an error is returned, it could have come from either the preparation
/// or execution of the statement.
///
/// On success, returns the number of rows modified or 0 if not applicable.
pub fn execute(&self, query: &str, params: &[&ToSql]) -> PostgresResult<uint> {
self.prepare(query).and_then(|stmt| stmt.execute(params))
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}
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/// Execute a sequence of SQL statements.
///
/// Statements should be separated by `;` characters. If an error occurs,
/// execution of the sequence will stop at that point. This is intended for
/// execution of batches of non-dynamic statements - for example, creation
/// of a schema for a fresh database.
///
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/// ## Warning
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///
/// Prepared statements should be used for any SQL statement which contains
/// user-specified data, as it provides functionality to safely embed that
/// data in the statment. Do not form statements via string concatenation
/// and feed them into this method.
///
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/// ## Example
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///
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/// ```rust,no_run
/// # use postgres::{PostgresConnection, PostgresResult};
/// fn init_db(conn: &PostgresConnection) -> PostgresResult<()> {
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/// conn.batch_execute("
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/// CREATE TABLE person (
/// id SERIAL PRIMARY KEY,
/// name NOT NULL
/// );
///
/// CREATE TABLE purchase (
/// id SERIAL PRIMARY KEY,
/// person INT NOT NULL REFERENCES person (id),
/// time TIMESTAMPTZ NOT NULL,
/// );
///
/// CREATE INDEX ON purchase (time);
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/// ")
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/// }
/// ```
pub fn batch_execute(&self, query: &str) -> PostgresResult<()> {
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let mut conn = self.conn.borrow_mut();
if conn.trans_depth != 0 {
return Err(PgWrongTransaction);
}
conn.quick_query(query).map(|_| ())
}
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/// Returns information used to cancel pending queries.
///
/// Used with the `cancel_query` function. The object returned can be used
/// to cancel any query executed by the connection it was created from.
pub fn cancel_data(&self) -> PostgresCancelData {
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self.conn.borrow().cancel_data
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}
/// Returns whether or not the stream has been desynchronized due to an
/// error in the communication channel with the server.
///
/// If this has occurred, all further queries will immediately return an
/// error.
pub fn is_desynchronized(&self) -> bool {
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self.conn.borrow().is_desynchronized()
}
/// Consumes the connection, closing it.
///
/// Functionally equivalent to the `Drop` implementation for
/// `PostgresConnection` except that it returns any error encountered to
/// the caller.
pub fn finish(self) -> PostgresResult<()> {
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let mut conn = self.conn.borrow_mut();
conn.finished = true;
conn.finish_inner()
}
fn canary(&self) -> u32 {
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self.conn.borrow().canary()
}
fn quick_query(&self, query: &str) -> PostgresResult<Vec<Vec<Option<String>>>> {
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self.conn.borrow_mut().quick_query(query)
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}
fn wait_for_ready(&self) -> PostgresResult<()> {
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self.conn.borrow_mut().wait_for_ready()
}
fn read_message(&self) -> IoResult<BackendMessage> {
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self.conn.borrow_mut().read_message()
}
fn write_messages(&self, messages: &[FrontendMessage]) -> IoResult<()> {
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self.conn.borrow_mut().write_messages(messages)
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}
}
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/// Specifies the SSL support requested for a new connection
pub enum SslMode {
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/// The connection will not use SSL
NoSsl,
/// The connection will use SSL if the backend supports it
PreferSsl(SslContext),
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/// The connection must use SSL
RequireSsl(SslContext)
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}
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/// Represents a transaction on a database connection.
///
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/// The transaction will roll back by default.
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pub struct PostgresTransaction<'conn> {
conn: &'conn PostgresConnection,
commit: Cell<bool>,
depth: u32,
finished: bool,
}
#[unsafe_destructor]
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impl<'conn> Drop for PostgresTransaction<'conn> {
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fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
}
}
impl<'conn> PostgresTransaction<'conn> {
fn finish_inner(&mut self) -> PostgresResult<()> {
debug_assert!(self.depth == self.conn.conn.borrow().trans_depth);
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let query = match (self.commit.get(), self.depth != 1) {
(false, true) => "ROLLBACK TO sp",
(false, false) => "ROLLBACK",
(true, true) => "RELEASE sp",
(true, false) => "COMMIT",
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};
self.conn.conn.borrow_mut().trans_depth -= 1;
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self.conn.quick_query(query).map(|_| ())
}
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/// Like `PostgresConnection::prepare`.
pub fn prepare<'a>(&'a self, query: &str) -> PostgresResult<PostgresStatement<'a>> {
if self.conn.conn.borrow().trans_depth != self.depth {
return Err(PgWrongTransaction);
}
self.conn.conn.borrow_mut().prepare(query, self.conn)
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}
/// Like `PostgresConnection::execute`.
pub fn execute(&self, query: &str, params: &[&ToSql]) -> PostgresResult<uint> {
self.prepare(query).and_then(|s| s.execute(params))
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}
/// Like `PostgresConnection::batch_execute`.
pub fn batch_execute(&self, query: &str) -> PostgresResult<()> {
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let mut conn = self.conn.conn.borrow_mut();
if conn.trans_depth != self.depth {
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return Err(PgWrongTransaction);
}
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conn.quick_query(query).map(|_| ())
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}
/// Like `PostgresConnection::transaction`.
pub fn transaction<'a>(&'a self) -> PostgresResult<PostgresTransaction<'a>> {
check_desync!(self.conn);
if self.conn.conn.borrow().trans_depth != self.depth {
return Err(PgWrongTransaction);
}
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try!(self.conn.quick_query("SAVEPOINT sp"));
self.conn.conn.borrow_mut().trans_depth += 1;
Ok(PostgresTransaction {
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conn: self.conn,
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commit: Cell::new(false),
depth: self.depth + 1,
finished: false,
})
}
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/// Executes a prepared statement, returning a lazily loaded iterator over
/// the resulting rows.
///
/// No more than `row_limit` rows will be stored in memory at a time. Rows
/// will be pulled from the database in batches of `row_limit` as needed.
/// If `row_limit` is less than or equal to 0, `lazy_query` is equivalent
/// to `query`.
pub fn lazy_query<'trans, 'stmt>(&'trans self,
stmt: &'stmt PostgresStatement,
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params: &[&ToSql],
row_limit: i32)
-> PostgresResult<PostgresLazyRows<'trans, 'stmt>> {
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if self.conn as *const _ != stmt.conn as *const _ {
return Err(PgWrongConnection);
}
check_desync!(self.conn);
stmt.lazy_query(row_limit, params).map(|result| {
PostgresLazyRows {
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_trans: self,
result: result
}
})
}
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/// Determines if the transaction is currently set to commit or roll back.
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pub fn will_commit(&self) -> bool {
self.commit.get()
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}
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/// Sets the transaction to commit at its completion.
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pub fn set_commit(&self) {
self.commit.set(true);
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}
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/// Sets the transaction to roll back at its completion.
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pub fn set_rollback(&self) {
self.commit.set(false);
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}
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/// A convenience method which consumes and commits a transaction.
pub fn commit(self) -> PostgresResult<()> {
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self.set_commit();
self.finish()
}
/// Consumes the transaction, commiting or rolling it back as appropriate.
///
/// Functionally equivalent to the `Drop` implementation of
/// `PostgresTransaction` except that it returns any error to the caller.
pub fn finish(mut self) -> PostgresResult<()> {
self.finished = true;
self.finish_inner()
}
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}
/// A prepared statement
pub struct PostgresStatement<'conn> {
conn: &'conn PostgresConnection,
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name: String,
param_types: Vec<PostgresType>,
result_desc: Vec<ResultDescription>,
next_portal_id: Cell<uint>,
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finished: bool,
}
#[unsafe_destructor]
impl<'conn> Drop for PostgresStatement<'conn> {
fn drop(&mut self) {
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if !self.finished {
let _ = self.finish_inner();
}
}
}
impl<'conn> PostgresStatement<'conn> {
fn finish_inner(&mut self) -> PostgresResult<()> {
check_desync!(self.conn);
try_pg!(self.conn.write_messages([
Close {
variant: 'S' as u8,
name: self.name.as_slice()
},
Sync]));
loop {
match try_pg!(self.conn.read_message()) {
ReadyForQuery { .. } => break,
ErrorResponse { fields } => {
try!(self.conn.wait_for_ready());
return Err(PgDbError(PostgresDbError::new(fields)));
}
_ => {}
}
}
Ok(())
}
fn inner_execute(&self, portal_name: &str, row_limit: i32, params: &[&ToSql])
-> PostgresResult<()> {
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if self.param_types.len() != params.len() {
return Err(PgWrongParamCount {
expected: self.param_types.len(),
actual: params.len(),
});
}
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let mut formats = vec![];
let mut values = vec![];
for (param, ty) in params.iter().zip(self.param_types.iter()) {
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let (format, value) = try!(param.to_sql(ty));
formats.push(format as i16);
values.push(value);
};
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let result_formats = Vec::from_elem(self.result_desc.len(), Binary as i16);
try_pg!(self.conn.write_messages([
Bind {
portal: portal_name,
statement: self.name.as_slice(),
formats: formats.as_slice(),
values: values.as_slice(),
result_formats: result_formats.as_slice()
},
Execute {
portal: portal_name,
max_rows: row_limit
},
Sync]));
match try_pg!(self.conn.read_message()) {
BindComplete => Ok(()),
ErrorResponse { fields } => {
try!(self.conn.wait_for_ready());
Err(PgDbError(PostgresDbError::new(fields)))
}
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_ => {
self.conn.conn.borrow_mut().desynchronized = true;
return Err(PgBadResponse);
}
}
}
fn lazy_query<'a>(&'a self, row_limit: i32, params: &[&ToSql])
-> PostgresResult<PostgresRows<'a>> {
let id = self.next_portal_id.get();
self.next_portal_id.set(id + 1);
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let portal_name = format!("{}p{}", self.name, id);
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try!(self.inner_execute(portal_name.as_slice(), row_limit, params));
let mut result = PostgresRows {
stmt: self,
name: portal_name,
data: RingBuf::new(),
row_limit: row_limit,
more_rows: true,
finished: false,
};
try!(result.read_rows())
Ok(result)
}
/// Returns a slice containing the expected parameter types.
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pub fn param_types(&self) -> &[PostgresType] {
self.param_types.as_slice()
}
/// Returns a slice describing the columns of the result of the query.
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pub fn result_descriptions(&self) -> &[ResultDescription] {
self.result_desc.as_slice()
}
/// Executes the prepared statement, returning the number of rows modified.
///
/// If the statement does not modify any rows (e.g. SELECT), 0 is returned.
///
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/// ## Example
///
/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
/// # let conn = PostgresConnection::connect("", &NoSsl).unwrap();
/// # let bar = 1i32;
/// # let baz = true;
/// let stmt = conn.prepare("UPDATE foo SET bar = $1 WHERE baz = $2").unwrap();
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/// match stmt.execute([&bar, &baz]) {
/// Ok(count) => println!("{} row(s) updated", count),
/// Err(err) => println!("Error executing query: {}", err)
/// }
pub fn execute(&self, params: &[&ToSql]) -> PostgresResult<uint> {
check_desync!(self.conn);
try!(self.inner_execute("", 0, params));
let num;
loop {
match try_pg!(self.conn.read_message()) {
DataRow { .. } => {}
ErrorResponse { fields } => {
try!(self.conn.wait_for_ready());
return Err(PgDbError(PostgresDbError::new(fields)));
}
CommandComplete { tag } => {
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let s = tag.as_slice().split(' ').last().unwrap();
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num = FromStr::from_str(s).unwrap_or(0);
break;
}
EmptyQueryResponse => {
num = 0;
break;
}
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_ => {
self.conn.conn.borrow_mut().desynchronized = true;
return Err(PgBadResponse);
}
}
}
try!(self.conn.wait_for_ready());
Ok(num)
}
/// Executes the prepared statement, returning an iterator over the
/// resulting rows.
///
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/// ## Example
///
/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
/// # let conn = PostgresConnection::connect("", &NoSsl).unwrap();
/// let stmt = conn.prepare("SELECT foo FROM bar WHERE baz = $1").unwrap();
/// # let baz = true;
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/// let mut rows = match stmt.query([&baz]) {
/// Ok(rows) => rows,
/// Err(err) => fail!("Error running query: {}", err)
/// };
/// for row in rows {
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/// let foo: i32 = row.get("foo");
/// println!("foo: {}", foo);
/// }
/// ```
pub fn query<'a>(&'a self, params: &[&ToSql]) -> PostgresResult<PostgresRows<'a>> {
check_desync!(self.conn);
self.lazy_query(0, params)
}
/// Consumes the statement, clearing it from the Postgres session.
///
/// Functionally identical to the `Drop` implementation of the
/// `PostgresStatement` except that it returns any error to the caller.
pub fn finish(mut self) -> PostgresResult<()> {
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self.finished = true;
self.finish_inner()
}
}
/// Information about a column of the result of a query.
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#[deriving(PartialEq, Eq)]
pub struct ResultDescription {
/// The name of the column
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pub name: String,
/// The type of the data in the column
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pub ty: PostgresType
}
/// An iterator over the resulting rows of a query.
pub struct PostgresRows<'stmt> {
stmt: &'stmt PostgresStatement<'stmt>,
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name: String,
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data: RingBuf<Vec<Option<Vec<u8>>>>,
row_limit: i32,
more_rows: bool,
finished: bool,
}
#[unsafe_destructor]
impl<'stmt> Drop for PostgresRows<'stmt> {
fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
}
}
impl<'stmt> PostgresRows<'stmt> {
fn finish_inner(&mut self) -> PostgresResult<()> {
check_desync!(self.stmt.conn);
try_pg!(self.stmt.conn.write_messages([
Close {
variant: 'P' as u8,
name: self.name.as_slice()
},
Sync]));
loop {
match try_pg!(self.stmt.conn.read_message()) {
ReadyForQuery { .. } => break,
ErrorResponse { fields } => {
try!(self.stmt.conn.wait_for_ready());
return Err(PgDbError(PostgresDbError::new(fields)));
}
_ => {}
}
}
Ok(())
}
fn read_rows(&mut self) -> PostgresResult<()> {
loop {
match try_pg!(self.stmt.conn.read_message()) {
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EmptyQueryResponse | CommandComplete { .. } => {
self.more_rows = false;
break;
},
PortalSuspended => {
self.more_rows = true;
break;
},
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DataRow { row } => self.data.push(row),
ErrorResponse { fields } => {
try!(self.stmt.conn.wait_for_ready());
return Err(PgDbError(PostgresDbError::new(fields)));
}
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_ => {
self.stmt.conn.conn.borrow_mut().desynchronized = true;
return Err(PgBadResponse);
}
}
}
self.stmt.conn.wait_for_ready()
}
fn execute(&mut self) -> PostgresResult<()> {
try_pg!(self.stmt.conn.write_messages([
Execute {
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portal: self.name.as_slice(),
max_rows: self.row_limit
},
Sync]));
self.read_rows()
}
/// Consumes the `PostgresRows`, cleaning up associated state.
///
/// Functionally identical to the `Drop` implementation on `PostgresRows`
/// except that it returns any error to the caller.
pub fn finish(mut self) -> PostgresResult<()> {
self.finished = true;
self.finish_inner()
}
fn try_next(&mut self) -> Option<PostgresResult<PostgresRow<'stmt>>> {
if self.data.is_empty() && self.more_rows {
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match self.execute() {
Ok(()) => {}
Err(err) => return Some(Err(err))
}
}
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self.data.pop_front().map(|row| {
Ok(PostgresRow {
stmt: self.stmt,
data: row
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})
})
}
}
impl<'stmt> Iterator<PostgresRow<'stmt>> for PostgresRows<'stmt> {
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#[inline]
fn next(&mut self) -> Option<PostgresRow<'stmt>> {
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// we'll never hit the network on a non-lazy result
self.try_next().map(|r| r.unwrap())
}
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#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
let lower = self.data.len();
let upper = if self.more_rows {
None
} else {
Some(lower)
};
(lower, upper)
}
}
/// A single result row of a query.
pub struct PostgresRow<'stmt> {
stmt: &'stmt PostgresStatement<'stmt>,
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data: Vec<Option<Vec<u8>>>
}
impl<'stmt> PostgresRow<'stmt> {
/// Retrieves the contents of a field of the row.
///
/// A field can be accessed by the name or index of its column, though
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/// access by index is more efficient. Rows are 0-indexed.
///
/// Returns an `Error` value if the index does not reference a column or
/// the return type is not compatible with the Postgres type.
pub fn get_opt<I, T>(&self, idx: I) -> PostgresResult<T> where I: RowIndex, T: FromSql {
let idx = match idx.idx(self.stmt) {
Some(idx) => idx,
None => return Err(PgInvalidColumn)
};
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FromSql::from_sql(&self.stmt.result_desc[idx].ty, &self.data[idx])
}
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/// Retrieves the contents of a field of the row.
///
/// A field can be accessed by the name or index of its column, though
/// access by index is more efficient. Rows are 0-indexed.
///
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/// ## Failure
///
/// Fails if the index does not reference a column or the return type is
/// not compatible with the Postgres type.
///
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/// ## Example
///
/// ```rust,no_run
/// # use postgres::{PostgresConnection, NoSsl};
/// # let conn = PostgresConnection::connect("", &NoSsl).unwrap();
/// # let stmt = conn.prepare("").unwrap();
/// # let mut result = stmt.query([]).unwrap();
/// # let row = result.next().unwrap();
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/// let foo: i32 = row.get(0u);
/// let bar: String = row.get("bar");
/// ```
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pub fn get<I, T>(&self, idx: I) -> T where I: RowIndex + fmt::Show + Clone, T: FromSql {
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match self.get_opt(idx.clone()) {
Ok(ok) => ok,
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Err(err) => fail!("error retrieving column {}: {}", idx, err)
}
}
}
impl<'stmt> Collection for PostgresRow<'stmt> {
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#[inline]
fn len(&self) -> uint {
self.data.len()
}
}
/// A trait implemented by types that can index into columns of a row.
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pub trait RowIndex {
/// Returns the index of the appropriate column, or `None` if no such
/// column exists.
fn idx(&self, stmt: &PostgresStatement) -> Option<uint>;
}
impl RowIndex for uint {
#[inline]
fn idx(&self, stmt: &PostgresStatement) -> Option<uint> {
if *self > stmt.result_desc.len() {
None
} else {
Some(*self)
}
}
}
impl<'a> RowIndex for &'a str {
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#[inline]
fn idx(&self, stmt: &PostgresStatement) -> Option<uint> {
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stmt.result_descriptions().iter().position(|d| d.name.as_slice() == *self)
}
}
/// A lazily-loaded iterator over the resulting rows of a query
pub struct PostgresLazyRows<'trans, 'stmt> {
result: PostgresRows<'stmt>,
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_trans: &'trans PostgresTransaction<'trans>,
}
impl<'trans, 'stmt> PostgresLazyRows<'trans, 'stmt> {
/// Like `PostgresRows::finish`.
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#[inline]
pub fn finish(self) -> PostgresResult<()> {
self.result.finish()
}
}
impl<'trans, 'stmt> Iterator<PostgresResult<PostgresRow<'stmt>>>
for PostgresLazyRows<'trans, 'stmt> {
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#[inline]
fn next(&mut self) -> Option<PostgresResult<PostgresRow<'stmt>>> {
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self.result.try_next()
}
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#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
self.result.size_hint()
}
}