Rename Page.printToPDF into page.pdf

This patch:
- renames Page.printToPDF into page.pdf
- adds a 'path' option to the page.pdf options instead of a separate
  `filePath` parameter
- improves on the documentation for the `page.pdf`

References #39.

README.md

@@ -96,7 +96,7 @@ However, if you're using Node 8 or higher, `async/await` make life easier:
 ```javascript
 browser.newPage().then(async page => {
   await page.setViewportSize({width: 1000, height: 1000});
-  await page.printToPDF('blank.pdf');
+  await page.pdf({path: 'blank.pdf'});
   browser.close();
 });
 ```

docs/api.md

@@ -35,8 +35,8 @@
   * [page.injectFile(filePath)](#pageinjectfilefilepath)
   * [page.mainFrame()](#pagemainframe)
   * [page.navigate(url, options)](#pagenavigateurl-options)
+  * [page.pdf(options)](#pagepdfoptions)
   * [page.plainText()](#pageplaintext)
-  * [page.printToPDF(filePath[, options])](#pageprinttopdffilepath-options)
   * [page.screenshot([options])](#pagescreenshotoptions)
   * [page.setContent(html)](#pagesetcontenthtml)
   * [page.setHTTPHeaders(headers)](#pagesethttpheadersheaders)
@@ -308,28 +308,58 @@ The `page.navigate` will throw an error if:
 - target URL is invalid.
 - the `maxTime` is exceeded during navigation.
 
+#### page.pdf(options)
+- `options` <[Object]> Options object which might have the following properties:
+  - `path` <[string]> The file path to save the PDF to.
+  - `scale` <[number]> Scale of the webpage rendering. Defaults to `1`.
+  - `displayHeaderFooter` <[boolean]> Display header and footer. Defaults to `false`.
+  - `printBackground` <[boolean]> Print background graphics. Defaults to `false`.
+  - `landscape` <[boolean]> Paper orientation. Defaults to `false`.
+  - `pageRanges` <[string]> Paper ranges to print, e.g., '1-5, 8, 11-13'. Defaults to the empty string, which means print all pages.
+  - `format` <[string]> Paper format. If set, takes priority over `width` or `height` options. Defaults to 'Letter'.
+  - `width` <[string]> Paper width, accepts values labeled with units.
+  - `height` <[string]> Paper height, accepts values labeled with units.
+  - `margin` <[Object]> Paper margins, defaults to none.
+    - `top` <[string]> Top margin, accepts values labeled with units.
+    - `right` <[string]> Right margin, accepts values labeled with units.
+    - `bottom` <[string]> Bottom margin, accepts values labeled with units.
+    - `left` <[string]> Left margin, accepts values labeled with units.
+- returns: <[Promise]<[Buffer]>> Promise which resolves with PDF buffer.
+
+The `width`, `height`, and `margin` options accept values labeled with units. Unlabeled values are treated as pixels.
+
+A few examples:
+- `page.pdf({width: 100})` - prints with width set to 100 pixels
+- `page.pdf({width: '100px'})` - prints with width set to 100 pixels
+- `page.pdf({width: '10cm'})` - prints with width set to 10 centimeters.
+
+All possible units are:
+- `px` - pixel
+- `in` - inch
+- `cm` - centimeter
+- `mm` - millimeter
+
+The `format` options are:
+- `Letter`: 8.5in x 11in
+- `Legal`: 8.5in x 14in
+- `Tabloid`: 11in x 17in
+- `Ledger`: 17in x 11in
+- `A0`: 33.1in x 46.8in
+- `A1`: 23.4in x 33.1in
+- `A2`: 16.5in x 23.4in
+- `A3`: 11.7in x 16.5in
+- `A4`: 8.27in x 11.7in
+- `A5`: 5.83in x 8.27in
+
 #### page.plainText()
 - returns:  <[Promise]<[string]>> Returns page's inner text.
 
-#### page.printToPDF(filePath[, options])
-- `filePath` <[string]> The file path to save the image to. The screenshot type will be inferred from file extension
-- `options` <[Object]> Options object which might have the following properties:
-	- `scale` <[number]>
-	- `displayHeaderFooter` <[boolean]>
-	- `printBackground` <[boolean]>
-	- `landscape` <[boolean]>
-	- `pageRanges` <[string]>
-	- `format` <[string]>
-	- `width` <[number]>
-	- `height` <[number]>
-- returns: <[Promise]> Promise which resolves when the PDF is saved.
-
 #### page.screenshot([options])
 - `options` <[Object]> Options object which might have the following properties:
     - `path` <[string]> The file path to save the image to. The screenshot type will be inferred from file extension.
-    - `type` <[string]> Specify screenshot type, could be either `jpeg` or `png`.
-    - `quality` <[number]> The quality of the image, between 0-100. Not applicable to `.png` images.
-    - `fullPage` <[boolean]> When true, takes a screenshot of the full scrollable page.
+    - `type` <[string]> Specify screenshot type, could be either `jpeg` or `png`. Defaults to 'png'.
+    - `quality` <[number]> The quality of the image, between 0-100. Not applicable to `png` images.
+    - `fullPage` <[boolean]> When true, takes a screenshot of the full scrollable page. Defaults to `false`.
     - `clip` <[Object]> An object which specifies clipping region of the page. Should have the following fields:
         - `x` <[number]> x-coordinate of top-left corner of clip area
         - `y` <[number]> y-coordinate of top-left corner of clip area

lib/Page.js

@@ -422,9 +422,9 @@ class Page extends EventEmitter {
   /**
    * @param {string} filePath
    * @param {!Object=} options
-   * @return {!Promise}
+   * @return {!Promise<!Buffer>}
    */
-  async printToPDF(filePath, options) {
+  async pdf(options) {
     options = options || {};
 
     let scale = options.scale || 1;
@@ -465,7 +465,9 @@ class Page extends EventEmitter {
       pageRanges: pageRanges
     });
     let buffer = new Buffer(result.data, 'base64');
-    fs.writeFileSync(filePath, buffer);
+    if (options.path)
+      fs.writeFileSync(options.path, buffer);
+    return buffer;
   }
 
   /**
@@ -652,7 +654,7 @@ function convertPrintParameterToInches(parameter) {
     console.assert(!isNaN(value), 'Failed to parse parameter value: ' + text);
     pixels = value * unitToPixels[unit];
   } else {
-    throw new Error('printToPDF Cannot handle parameter type: ' + (typeof parameter));
+    throw new Error('page.pdf() Cannot handle parameter type: ' + (typeof parameter));
   }
   return pixels / 96;
 }

phantom_shim/WebPage.js

@@ -405,7 +405,8 @@ class WebPage {
       options.landscape = paperSize.orientation === 'landscape';
       options.width = paperSize.width;
       options.height = paperSize.height;
-      await(this._page.printToPDF(fileName, options));
+      options.path = fileName;
+      await(this._page.pdf(options));
     } else {
       let options = {};
       if (this.clipRect && (this.clipRect.left || this.clipRect.top || this.clipRect.width || this.clipRect.height)) {

test/test.js

@@ -829,7 +829,7 @@ describe('Puppeteer', function() {
     }));
   });
 
-  describe('Page.printToPDF', function() {
+  describe('Page.pdf', function() {
     let outputFile = __dirname + '/assets/output.pdf';
     afterEach(function() {
       fs.unlinkSync(outputFile);
@@ -837,7 +837,7 @@ describe('Puppeteer', function() {
 
     it('should print to pdf', SX(async function() {
       await page.navigate(PREFIX + '/grid.html');
-      await page.printToPDF(outputFile);
+      await page.pdf({path: outputFile});
       expect(fs.readFileSync(outputFile).byteLength).toBeGreaterThan(0);
     }));
   });