Added --replace options for string replacement in html response bodies

bin/livestyle

@@ -6,6 +6,7 @@ var express = require('express'),
     util = require('util'),
     path = require('path'),
     mappings = {},
+    replacements = {},
     optimist = require('optimist'),
     commandLineOptions = optimist
         .usage('Usage: $0 [--proxy <remotehost> [-m <directoryMapping>]] [-d] [-h <hostname>] [-p <port>] [--root directory]')
@@ -58,6 +59,9 @@ var express = require('express'),
             alias: 'm',
             describe: 'Directory mappings of the form: remoteDir=localDir where localDir is relative to the root directory unless prefixed with /'
         })
+        .options('replace', {
+            describe: 'Low level string replacement run on your html response strings. Useful to reroute http URLs to local disk. This could break your html!'
+        })
         .options('host', {
             alias: 'h',
             default: '0.0.0.0',
@@ -85,6 +89,17 @@ var express = require('express'),
                     }
                 });
             }
+
+            if (argv.replace) {
+                (typeof argv.replace === 'string' ? [argv.replace] : argv.replace).forEach(function (urlEqualsDir) {
+                    var matchUrlEqualsDir = urlEqualsDir.match(/^([^=]+)=([^=]+)$/);
+                    if (matchUrlEqualsDir) {
+                        replacements[matchUrlEqualsDir[1]] = matchUrlEqualsDir[2];
+                    } else {
+                        throw 'Invalid --replace syntax: ' + urlEqualsDir;
+                    }
+                });
+            }
         })
         .argv,
         root;
@@ -123,6 +138,7 @@ var server = require('../lib/createLiveStyleApp')({
     jsxtransform: commandLineOptions.jsxtransform,
     processImage: commandLineOptions.processimage,
     mappings: mappings,
+    replacements: replacements,
     proxy: commandLineOptions.proxy || null
 }).listen(commandLineOptions.port, commandLineOptions.host);
 

lib/createLiveStyleApp.js

@@ -30,6 +30,10 @@ module.exports = function createLiveStyleApp(options) {
 
     app.use(require('./middleware/bufferDataEventsUntilFirstListener')());
 
+    if (options.replacements) {
+      app.use(require('./middleware/replaceString')(options.replacements));
+    }
+
     if (!options.dead) {
         app.use(require('./middleware/injectLiveStyleScriptIncludeIntoHtml')(options));
     }

lib/middleware/replaceString.js

@@ -0,0 +1,56 @@
+var hijackResponse = require('hijackresponse');
+var escapeStringRegexp = require('escape-string-regexp');
+
+module.exports = function (replacements) {
+    replacements = replacements || {};
+
+    return function injectLiveStyleScriptIncludeIntoHtml(req, res, next) {
+
+        if (req.get('X-Requested-With') !== 'XMLHttpRequest' && req.method === 'GET' && (req.accepts('html') || (req.headers.accept && req.headers.accept.indexOf('*/*') !== -1))) {
+            // Prevent If-None-Match revalidation with the downstream middleware with ETags that aren't suffixed with "-livestyle":
+            var ifNoneMatch = req.headers['if-none-match'];
+            if (ifNoneMatch) {
+                var validIfNoneMatchTokens = ifNoneMatch.split(" ").filter(function (etag) {
+                    return /-(?:livestyle|processimage|compiless|compile-sass)\"$/.test(etag);
+                });
+                if (validIfNoneMatchTokens.length > 0) {
+                    req.headers['if-none-match'] = validIfNoneMatchTokens.join(" ");
+                } else {
+                    delete req.headers['if-none-match'];
+                }
+            }
+            delete req.headers['if-modified-since'];
+            delete req.headers['content-length'];
+            delete req.headers['accept-encoding'];
+
+            hijackResponse(res, function (err, res) {
+                if (err) {
+                    return res.unhijack(function () {
+                        next(err);
+                    });
+                }
+                var contentType = res.getHeader('content-type');
+                if (!contentType || !contentType.match(/^text\/html(?:;\s*charset=('|"|)([^'"]+)\1)?$/i)) {
+                    res.unhijack(true);
+                } else {
+
+                    res.removeHeader('content-length');
+                    res.removeHeader('last-modified');
+                    res.writeHead(res.statusCode);
+
+                    var chunks = [];
+                    res.on('data', function (chunk) {
+                        chunks.push(chunk);
+                    }).on('end', function () {
+                        var htmlStr = Object.keys(replacements).reduce(function (html, needle) {
+                            return html.replace(new RegExp(escapeStringRegexp(needle), 'gi'), replacements[needle]);
+                        }, chunks.join(''));
+
+                        res.end(htmlStr);
+                    });
+                }
+            });
+        }
+        next();
+    };
+};

package.json

@@ -26,6 +26,7 @@
   },
   "dependencies": {
     "errorhandler": "1.4.2",
+    "escape-string-regexp": "^1.0.3",
     "express": "4.13.3",
     "express-autoprefixer": "4.0.3",
     "express-compile-sass": "^3.0.4",