Add pdf generator using gitbook-pdf

lib/generate/index.js

@@ -9,6 +9,7 @@ var parse = require("../parse");
 var generators = {
     "site": require("./site"),
     "page": require("./page"),
+    "pdf": require("./pdf"),
     "json": require("./json")
 };
 

lib/generate/pdf/Index.js

@@ -0,0 +1,56 @@
+var util = require("util");
+var path = require("path");
+var Q = require("q");
+var _ = require("lodash");
+var exec = require('child_process').exec;
+
+var fs = require("../fs");
+var parse = require("../../parse");
+var BaseGenerator = require("../page");
+
+/*
+ *  This generator inherits from the single page generator
+ *  and convert the page output to pdf using gitbook-pdf
+ */
+var Generator = function() {
+    BaseGenerator.apply(this, arguments);
+
+    // Options for PDF generation
+    this.options = _.defaults(this.options, {
+        format: "A4"
+    });
+};
+util.inherits(Generator, BaseGenerator);
+
+Generator.prototype.finish = function() {
+    var that = this;
+
+    return BaseGenerator.prototype.finish.apply(this)
+    .then(function() {
+        var d = Q.defer();
+
+        var command = [
+            "gitbook-pdf",
+            "generate",
+            path.join(that.options.output, "index.html"),
+            path.join(that.options.output, "index.pdf"),
+            "--format="+that.options.format
+        ].join(" ");
+
+        exec(command, function (error, stdout, stderr) {
+            if (error) {
+                if (error.code == 127) {
+                    error.message = "Need to install gitbook-pdf using: npm install gitbook-pdf -g";
+                } else {
+                    error.message = error.message + " "+stdout;
+                }
+                return d.reject(error);
+            }
+            d.resolve();
+        });
+
+        return d.promise;
+    });
+};
+
+module.exports = Generator;