Allow LibreOffice to be used when exporting a pad

This commit adds support for LibreOffice when exporting a pad to doc, pdf, ..

This commit also cleans up some export logic when exporting to txt

settings.json.template

@@ -86,10 +86,14 @@
      may cause problems during deployment. Set to 0 to disable caching */
   "maxAge" : 21600, // 60 * 60 * 6 = 6 hours
 
-  /* This is the path to the Abiword executable. Setting it to null, disables abiword.
+  /* This is the absolute path to the Abiword executable. Setting it to null, disables abiword.
      Abiword is needed to advanced import/export features of pads*/
   "abiword" : null,
 
+  /* This is the absolute path to the soffice executable. Setting it to null, disables LibreOffice exporting.
+     LibreOffice can be used in lieu of Abiword to export pads */
+  "soffice" : null,
+
   /* This is the path to the Tidy executable. Setting it to null, disables Tidy.
      Tidy is used to improve the quality of exported pads*/
   "tidyHtml" : null,

src/node/handler/ExportHandler.js

@@ -30,9 +30,15 @@ var os = require('os');
 var hooks = require("ep_etherpad-lite/static/js/pluginfw/hooks");
 var TidyHtml = require('../utils/TidyHtml');
 
+var convertor = null;
+
 //load abiword only if its enabled
 if(settings.abiword != null)
-  var abiword = require("../utils/Abiword");
+  convertor = require("../utils/Abiword");
+
+// Use LibreOffice if an executable has been defined in the settings
+if(settings.soffice != null)
+  convertor = require("../utils/LibreOffice");
 
 var tempDirectory = "/tmp";
 
@@ -70,71 +76,11 @@ exports.doExport = function(req, res, padId, type)
       }
       else if(type == "txt")
       {
-        var txt;
+        exporttxt.getPadTXTDocument(padId, req.params.rev, false, function(err, txt)
-        var randNum;
-        var srcFile, destFile;
-
-        async.series([
-          //render the txt document
-          function(callback)
         {
-            exporttxt.getPadTXTDocument(padId, req.params.rev, false, function(err, _txt)
+          if(ERR(err)) return;
-            {
-              if(ERR(err, callback)) return;
-              txt = _txt;
-              callback();
-            });
-          },
-          //decide what to do with the txt export
-          function(callback)
-          {
-            //if this is a txt export, we can send this from here directly
           res.send(txt);
-            callback("stop");
+        });
-          },
-          //send the convert job to abiword
-          function(callback)
-          {
-            //ensure html can be collected by the garbage collector
-            txt = null;
-
-            destFile = tempDirectory + "/etherpad_export_" + randNum + "." + type;
-            abiword.convertFile(srcFile, destFile, type, callback);
-          },
-          //send the file
-          function(callback)
-          {
-            res.sendFile(destFile, null, callback);
-          },
-          //clean up temporary files
-          function(callback)
-          {
-            async.parallel([
-              function(callback)
-              {
-                fs.unlink(srcFile, callback);
-              },
-              function(callback)
-              {
-                //100ms delay to accomidate for slow windows fs
-                if(os.type().indexOf("Windows") > -1)
-                {
-                  setTimeout(function()
-                  {
-                    fs.unlink(destFile, callback);
-                  }, 100);
-                }
-                else
-                {
-                  fs.unlink(destFile, callback);
-                }
-              }
-            ], callback);
-          }
-        ], function(err)
-        {
-          if(err && err != "stop") ERR(err);
-        })
       }
       else
       {
@@ -183,11 +129,11 @@ exports.doExport = function(req, res, padId, type)
             TidyHtml.tidy(srcFile, callback);
           },
 
-          //send the convert job to abiword
+          //send the convert job to the convertor (abiword, libreoffice, ..)
           function(callback)
           {
             destFile = tempDirectory + "/etherpad_export_" + randNum + "." + type;
-            abiword.convertFile(srcFile, destFile, type, callback);
+            convertor.convertFile(srcFile, destFile, type, callback);
           },
           //send the file
           function(callback)

src/node/utils/ExportHtml.js

@@ -488,6 +488,9 @@ exports.getPadHTMLDocument = function (padId, revNum, noDocType, callback)
         (noDocType ? '' : '<!doctype html>\n') +
         '<html lang="en">\n' + (noDocType ? '' : '<head>\n' +
           '<title>' + Security.escapeHTML(padId) + '</title>\n' +
+          '<meta name="generator" content="Etherpad Lite">\n' +
+          '<meta name="author" content="Etherpad Lite">\n' +
+          '<meta name="changedby" content="Etherpad Lite">\n' +
           '<meta charset="utf-8">\n' +
           '<style> * { font-family: arial, sans-serif;\n' +
             'font-size: 13px;\n' +

src/node/utils/LibreOffice.js

@@ -0,0 +1,93 @@
+/**
+ * Controls the communication with LibreOffice
+ */
+
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+var async = require("async");
+var fs = require("fs");
+var os = require("os");
+var path = require("path");
+var settings = require("./Settings");
+var spawn = require("child_process").spawn;
+
+// Conversion tasks will be queued up, so we don't overload the system
+var queue = async.queue(doConvertTask, 1);
+
+/**
+ * Convert a file from one type to another
+ *
+ * @param  {String}     srcFile     The path on disk to convert
+ * @param  {String}     destFile    The path on disk where the converted file should be stored
+ * @param  {String}     type        The type to convert into
+ * @param  {Function}   callback    Standard callback function
+ */
+exports.convertFile = function(srcFile, destFile, type, callback) {
+  queue.push({"srcFile": srcFile, "destFile": destFile, "type": type, "callback": callback});
+};
+
+function doConvertTask(task, callback) {
+  var tmpDir = os.tmpdir();
+
+  async.series([
+    // Generate a PDF file with LibreOffice
+    function(callback) {
+      var soffice = spawn(settings.soffice, [
+        '--headless',
+        '--invisible',
+        '--nologo',
+        '--nolockcheck',
+        '--convert-to', task.type,
+        task.srcFile,
+        '--outdir', tmpDir
+      ]);
+
+      var stdoutBuffer = '';
+
+      // Delegate the processing of stdout to another function
+      soffice.stdout.on('data', function(data) {
+        stdoutBuffer += data.toString();
+      });
+
+      // Append error messages to the buffer
+      soffice.stderr.on('data', function(data) {
+        stdoutBuffer += data.toString();
+      });
+
+      // Throw an exception if libreoffice failed
+      soffice.on('exit', function(code) {
+        if (code != 0) {
+          return callback("LibreOffice died with exit code " + code + " and message: " + stdoutBuffer);
+        }
+
+        callback();
+      })
+    },
+
+    // Move the PDF file to the correct place
+    function(callback) {
+      var filename = path.basename(task.srcFile);
+      var pdfFilename = filename.substr(0, filename.lastIndexOf('.')) + '.' + task.type;
+      var pdfPath = path.join(tmpDir, pdfFilename);
+      fs.rename(pdfPath, task.destFile, callback);
+    }
+  ], function(err) {
+    // Invoke the callback for the local queue
+    callback();
+
+    // Invoke the callback for the task
+    task.callback(err);
+  });
+}

src/node/utils/Settings.js

@@ -152,6 +152,11 @@ exports.minify = true;
  */
 exports.abiword = null;
 
+/**
+ * The path of the libreoffice executable
+ */
+exports.soffice = null;
+
 /**
  * The path of the tidy executable
  */