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installLiveCssFileWatcherInServer: Watch the containing directory ins…
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…tead of the file when using fs.watch.

Hopefully this resolves some of the weirdness we've seen (see #23).
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@papandreou
papandreou committed Mar 17, 2012
1 parent 69c5a19 commit a19fadf
Showing 1 changed file with 101 additions and 69 deletions.
170 changes: 101 additions & 69 deletions lib/installLiveCssFileWatcherInServer.js
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@@ -1,57 +1,108 @@
var fs = require('fs'),
path = require('path'),
URL = require('url'),
clientsByFileName = {},
mtimeByFileName = {};

function buildRelativeUrl(fromUrl, toUrl) {
var minLength = Math.min(fromUrl.length, toUrl.length),
commonPrefixLength = 0;
while (commonPrefixLength < minLength && fromUrl[commonPrefixLength] === toUrl[commonPrefixLength]) {
commonPrefixLength += 1;
}
var commonPrefix = fromUrl.substr(0, commonPrefixLength),
commonPrefixMatch = commonPrefix.match(/^(file:\/\/|[^:]+:\/\/[^\/]+\/)/);
URL = require('url');

if (!path.relative) {
// Add path.relative for node.js < 0.6 (taken from 0.6.13)
// path.relative(from, to)
path.relative = function(from, to) {
from = path.resolve(from).substr(1);
to = path.resolve(to).substr(1);

function trim(arr) {
var start = 0;
for (; start < arr.length; start++) {
if (arr[start] !== '') break;
}

var end = arr.length - 1;
for (; end >= 0; end--) {
if (arr[end] !== '') break;
}

if (commonPrefixMatch) {
var fromFragments = fromUrl.substr(commonPrefixMatch[1].length).replace(/^\/+/, "").replace(/[^\/]+$/, "").split(/\//),
toFragments = toUrl.substr(commonPrefixMatch[1].length).replace(/^\/+/, "").split(/\//);
if (start > end) return [];
return arr.slice(start, end - start + 1);
}

fromFragments.pop();
var fromParts = trim(from.split('/'));
var toParts = trim(to.split('/'));

var i = 0;
while (i < fromFragments.length && i < toFragments.length && fromFragments[i] === toFragments[i]) {
i += 1;
var length = Math.min(fromParts.length, toParts.length);
var samePartsLength = length;
for (var i = 0; i < length; i++) {
if (fromParts[i] !== toParts[i]) {
samePartsLength = i;
break;
}
}
var relativeUrl = toFragments.slice(i).join("/");
while (i < fromFragments.length) {
relativeUrl = '../' + relativeUrl;
i += 1;

var outputParts = [];
for (var i = samePartsLength; i < fromParts.length; i++) {
outputParts.push('..');
}
return relativeUrl;
} else {
return toUrl; // No dice
}

outputParts = outputParts.concat(toParts.slice(samePartsLength));

return outputParts.join('/');
};
}

function clientToString(client) {
return client.handshake.address.address + ':' + client.handshake.address.port;
}

module.exports = function (app, options, sio) {
var io = sio.listen(app);
var io = sio.listen(app),
clientsByFileName = {},
isWatchedByDirName = {},
mtimeByFileName = {};

function notifyWatchers(fileName) {
if (fileName in clientsByFileName) {
var rootRelativePath = '/' + path.relative(options.documentRoot, fileName);
if (options.debug && clientsByFileName[fileName].length) {
console.warn(' Notifying ' + clientsByFileName[fileName].length + ' watcher(s):\n ' +
clientsByFileName[fileName].map(clientToString).join('\n '));
}
clientsByFileName[fileName].forEach(function (client) {
client.emit('change', rootRelativePath);
});
}
}

function notifyWatchersIfMtimeIncreased(fileName, eventName) {
if (fileName in clientsByFileName) {
if (!(fileName in mtimeByFileName)) {
mtimeByFileName[fileName] = Infinity;
notifyWatchers(fileName);
} else {
fs.stat(fileName, function (err, stats) {
if (err) {
return;
}
if (stats.mtime > mtimeByFileName[fileName]) {
notifyWatchers(fileName);
} else if (options.debug) {
console.warn('Suppressing notification for ' + fileName + ', the mtime of the file is still the same');
}
mtimeByFileName[fileName] = stats.mtime;
});
}
}
}

if (!options.debug) {
io.set('log level', 1);
}
io.sockets.on('connection', function (client) {
if (options.debug) {
console.warn('Client ' + clientToString(client) + ' connected');
}
client.on('watch', function (assetUrls) {
client.on('watch', function (rootRelativePaths) {
if (options.debug) {
console.warn('Client subscribed to ' + assetUrls.length + ' file(s):');
console.warn('Client subscribed to ' + rootRelativePaths.length + ' file(s):');
}
assetUrls.forEach(function (rootRelativePath) {
rootRelativePaths.forEach(function (rootRelativePath) {
if (options.debug) {
console.warn(' ' + rootRelativePath);
}
Expand All @@ -73,50 +124,31 @@ module.exports = function (app, options, sio) {
} else {
clientsByFileName[fileName] = [client];

function notifyWatchers () {
if (options.debug) {
console.warn(fileName + ' changed on disc');
if (clientsByFileName[fileName].length) {
console.warn(' Notifying ' + clientsByFileName[fileName].length + ' watcher(s):\n ' +
clientsByFileName[fileName].map(clientToString).join('\n '));
}
}
clientsByFileName[fileName].forEach(function (client) {
client.emit('change', rootRelativePath);
});
}

if (options.debug) {
console.warn(' Starting to watch ' + fileName + ' using ' + ((fs.watch && !options.watchfile) ? 'fs.watch' : 'fs.watchFile'));
}
if (fs.watch && !options.watchfile) {
fs.watch(fileName, function handleWatchNotification(event) {
// Resubscribe if the file is renamed (Mac OSX):
if (event === 'rename') {
fs.watch(fileName, handleWatchNotification);
}
if (!(fileName in mtimeByFileName)) {
mtimeByFileName[fileName] = Infinity;
notifyWatchers();
} else {
fs.stat(fileName, function (err, stats) {
if (err) {
return;
}
if (stats.mtime > mtimeByFileName[fileName]) {
notifyWatchers();
} else if (options.debug) {
console.warn("Ignoring " + event + " from fs.watch, the mtime of the file is still the same");
}
mtimeByFileName[fileName] = stats.mtime;
});
var dirName = path.dirname(fileName);
if (!isWatchedByDirName[dirName]) {
if (options.debug) {
console.warn('Starting to ' + dirName + ' using fs.watch');
}
});
fs.watch(dirName, function (eventName, fileName) {
fileName = path.resolve(dirName, fileName); // Absolutify fileName
if (options.debug) {
console.warn('fs.watch: ' + eventName + ' ' + fileName);
}
notifyWatchersIfMtimeIncreased(fileName, eventName);
});
}
} else {
// TODO: Poll the upstream server if the file isn't found on disc (or no documentRoot is specified)
if (options.debug) {
console.warn('Starting to watch ' + fileName + ' using fs.watchFile');
}
fs.watchFile(fileName, function (currStat, prevStat) {
if (options.debug) {
console.warn('fs.watchFile: ' + fileName + ' changed on disc');
}
if (currStat.mtime.getTime() !== prevStat.mtime.getTime()) {
notifyWatchers();
notifyWatchers(fileName);
}
});
}
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