Selenium itself cannot interact with system-level dialogs
opened by JS in the browser. In order to download PDFs as part of the browser
automation process, it requires the help from either additional frameworks or
an approach that handles the downloads automatically, and prevent Firefox from
popping up the "Save file" dialog.
One way is to use the Firefox preferences to download the
files directly without going through the dialog box, and here is the code that
will do just that.
This approach is better as we don't have to use custom/third party software to deal with the dialog boxes separately, which can become tedious and difficult to integrate with the already existing complex setup we usually have for selenium.
public WebDriver getFireFoxProfileDriverForDownload(){
String downloadFolderPath = "C:\\All_Downloads\\Java";
//creating an object for the profiles
ProfilesIni allProfiles = new ProfilesIni();
//getting the firefox profile for webdriver, which was created manually
FirefoxProfile profile = allProfiles.getProfile("webdriverprofile");
//Setting the preferences for download -
profile.setPreference("browser.download.folderList",2);
profile.setPreference("browser.download.dir", downloadFolderPath);
profile.setPreference("browser.helperApps.neverAsk.saveToDisk","application/pdf");
//Prevent Firefox from previewing PDFs -
profile.setPreference("pdfjs.disabled",true);
//Disabling the third party PDF viewers -
profile.setPreference("plugin.scan.plid.all",false);
profile.setPreference("plugin.scan.Acrobat","90.0");
profile.setPreference("plugin.disable_full_page_plugin_for_types","application/pdf");
//instantiating the firefox browser with this new profile
WebDriver firefoxDriver = new FirefoxDriver(profile);
//This driver instance can now be used to open firefox with the above preferences
return firefoxDriver;
}
Description of the
code above -
·
Setting
the preferences for download -
The preferences can be set using the setPreference method of
the FirefoxProfile class. This method needs the value of the preferences in
key-value pairs, where the key is the name of the preference and the value is
the option that you want to set it to. The name and acceptable/allowable values
for the preferences can be found by browsing the 'config' properties of the
firefox, via the 'about:config' page. The key would be the 'Preference Name'
and the value would be the 'Value', as seen from the 'config' window of the
firefox.
Firefox’s download manager preferences can be set
programmatically while instantiating FirefoxDriver. The following properties
can be used for this.
- "browser.download.folderList" - This controls the default folder to download a file to. 0 indicates the Desktop, 1 indicates the systems default downloads location and 2 indicates a custom folder.
- "browser.download.dir" - This holds the custom destination folder for downloading. It is activated if browser.download.folderList has been set to 2.
- "browser.helperApps.neverAsk.saveToDisk" - This stores a comma-separated list of MIME types to save to disk without asking what to use to open the file.
The MIME type defined here is "application/pdf",
which is a type that most PDF files use. However, if the target PDF file has a
non-standard MIME type, then “Save file” dialog might still show up. In order
to fix this issue, the actual MIME type has to be added into
browser.helperApps.neverAsk.saveToDisk property, which can be checked out using
either of the following approaches:
- Upload file to online tools like - http://mime.ritey.com/
- Download file and monitor MIME type in Chrome’s developer tool or web debugging proxy like Fiddler, CharlesProxy, etc.
·
Prevent
Firefox from previewing PDFs -
With the release of Firefox 19.0, PDF.js has been integrated
into Firefox to provide built-in ability of displaying PDF files inside
browser. It tries to parse and render PDFs into HTML5, which can be automated
using Selenium WebDriver in theory. However, to download PDFs instead of
preview in Firefox, another about:config entry needs to be changed to disable
PDF.js.
·
Disabling
the third party PDF viewers -
Except for Firefox’s built-in PDF viewer, there might be
other third party plugins preventing Firefox from downloading PDFs
automatically. If a machine has Adobe Reader installed, then default PDF
viewing setting in Firefox might have been set to Adobe Acrobat without notice.
To avoid previewing PDFs with those plugins, two more
about:config entries need to be configured when starting WebDriver instance.
- "plugin.scan.plid.all" - This needs to be set to false, so that Firefox won’t scan and load plugins.
- "plugin.scan.Acrobat" - This is a key that holds the minimum allowed version number that Adobe Acrobat is allowed to launch. Setting it to a number larger than currently installed Adobe Acrobat version should do the trick.
- "plugin.disable_full_page_plugin_for_types" = "application/pdf" - Without this, the pdf gets opened in the browser itself, instead of getting downloaded.
