HTML to PNG Server by Adam Hooper <adam@adamhooper.com> PURPOSE This program accepts HTML and outputs PNG representations of it. FEATURES - Runs as an HTTP server on port 20558 - Renders with multiple strategies: - Internet Explorer on Windows - Gecko on Ubuntu Linux - Firefox 3.0 and above on all platforms - Can crop images from different rendering strategies so their outputs correspond, ideally pixel-for-pixel. REQUIREMENTS You must have a Java 6.0 runtime available. Individual rengering strategies have thier own requirements. (Peruse their source code for details.) USAGE This server is intended for a distributed environment (or, at least, an environment which you foresee to be distributed in the future.) The server should be run on each "renderer" node--that is, the computer which will perform the actual rendering, as opposed to the client which will manipulate those results. To start the server: java -jar /path/to/html_to_png_server.jar A client may request a PNG from the server by sending a utf-8 POST request to "http://node.domain.or.ip.address:20558/STRATEGY", where "STRATEGY" is one of "ff3-linux", "ie", or anything else registered in HtmlToPngHttpServer.java. The POST request should consist exclusively of utf8-encoded HTML; the server will respond with PNG data. CLIENTS Known clients include: - html_render, by Adam Hooper http://github.com/adamh/html_render/tree/master A Ruby library which provides an API to html_to_png_server (including multi-threaded, distributed rendering) with special classes for integrating with unit testing libraries. STRATEGIES IE (http://server/ie) how it works: it extracts a custom executable into a temporary directory and executes it. requires: .NET 2.0 platform or above how it could improve: - it could be sped up - it could be made to work without logging on (for a graphics context) - its license could be clarified (it is a copy/paste mix-and-match from Internet forums) tips: use a different computer (or virtual machine) for each different version of Internet Explorer. GECKO ON LINUX (http://server/ff3-linux) how it works: it executes "gnome-web-photo", assumed to be in the user's path requires: the "gnome-web-photo" Ubuntu package (or equivalent) how it could improve: - it could be sped up tips: run this Java server in an Xvfb instance to avoid the need to log in (for instance, "xvfb-run java -jar html_to_png_server/html_to_png_server.jar") FIREFOX THROUGH MOZREPL (http://server/mozrepl) how it works: it acts (kind of) like a proxy to a MozRepl screenshot server. requires: "mozrepl" Firefox extension - http://wiki.github.com/bard/mozrepl installation: 1. Install "mozrepl" from http://wiki.github.com/bard/mozrepl 2. Copy vendor/moz-repl-screenshot-server.js somewhere local and permanent 3. Open Firefox and browse to "about:config" 4. Set "extensions.mozrepl.defaultInteractor" to "screenshot" 5. Set "extensions.mozrepl.initUrl" to "file:///.../moz-repl-screenshot-server.js" (where "..." is the location you chose to save the file in Step 2). 6. Set "extensions.mozrepl.autoStart" to "true" 7. Click Tools -> MozRepl -> Start path you chose to save how it could improve: - installation could be made simpler - it could be made not to require a running Firefox instance - it could be made to work without logging on (for a graphics context). (On UNIX-like systems, at least, "xvfb-run" can circumvent this.) SAFARI ON OS X (http://server/webkit2png) how it works: it extracts webkit2png into a temporary directory and executes it. See http://github.com/paulhammond/webkit2png requires: See http://github.com/paulhammond/webkit2png - On OSX, use "Java Preferences" and ensure you are on Java 6 - Aside from that, everything should work by default - OSX is notoriously difficult to run in a VM, so "a Mac" is one of the requirements how it could improve: - it could be sped up - it could be made to work without logging on (for a graphics context) DEVELOPMENT The code is fairly (though by no means expertly) organized, though cut/pasted too heavily. Open this folder in Eclipse and enjoy yourself. Feel free to send me any patches, generated through "git format-patch" or, slightly less helpfully, "diff -u". I will concern myself with regenerating "ie-thumbnail-generator.exe" and "html_to_png_server.jar". As far as I can see, the client/server API will not change. As for this server's internals: no APIs should be considered stable. LICENSE I believe in software freedom, and that includes the freedom for that software to be relicensed or otherwise taken out of my control. This code is all released under the Public Domain, or as to Public Domain as is legally sensible. I declare myself absolved of my copyright on this code. Exception: Files in the vendor/ directory were not written by me; I have tried to faithfully copy their licenses here.