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event-source.js
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event-source.js
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var Writable = require('stream').Writable;
var crypto = require('crypto');
var url = require('url');
var util = require('util');
var path = require('path');
var fs = require('fs');
var Counter = require('stream-counter');
var mkdirp = require('mkdirp');
var rimraf = require('rimraf');
var Changes = require('changes-stream');
var SeqFile = require('seq-file');
var http = require('http-https');
var parse = require('parse-json-response');
var version = require('./package.json').version;
var ua = 'npm-ev-source/' + version + ' node/' + process.version;
var noop = function () {}
module.exports = EventSource;
util.inherits(EventSource, Writable);
function EventSource(options) {
if (!(this instanceof EventSource)) { return new EventSource(options) }
Writable.call(this, { highWaterMark: 16, objectMode: true });
options = options || {};
//
// URLs and such
//
this.skim = options.skim || 'https://skimdb.npmjs.com/registry';
if (!options.eventSource) { throw new Error('Need eventSource DB to populate') }
//
// Setup both public and private urls (public needed for attachment creation)
//
var es = url.parse(options.eventSource);
this.eventSource = es.href.replace(/\/+$/, '');
delete es.auth;
this.pubEventSource = url.format(es).replace(/\/+$/, '');
this.seqFile = new SeqFile(options.seqFile || 'sequence.seq');
this.missingLog = options.missingLog || false;
//
// Follow Opts
//
this.inactivity_ms = options.inactivity_ms || 60 * 60 * 1000;
this.since = 0;
this.follow = undefined;
//
// optional things
//
this.ua = options.ua || ua;
this.tmp = options.tmp;
this.registry = options.registry || undefined;
//
// Prefix for _ keys that are currently in the nested level documents.
// This is bad practice with couchdb and it rejects them in most cases
//
this._prefix = 'npm:';
//
// Default boundary for multipart/related requests
//
this.boundary = 'npm-ev-source-' + crypto.randomBytes(6).toString('base64');
//
// Randomish dir so we donr reuse one potentially when debugging
//
if(!this.tmp) {
var c = crypto.randomBytes(6).toString('hex');
this.tmp = 'npm-ev-source-tmp-' + process.pid + '-' + c;
}
this.seqFile.read(this.onSeq.bind(this));
};
//
// Callback of SeqFile function that reads from the specified file
//
EventSource.prototype.onSeq = function (err, data) {
//
// Errors don't matter, we just default to `this.since`
//
this.since = +data || this.since;
this.start();
};
//
// Start following the skimdb database and get the changes!
//
EventSource.prototype.start = function () {
this.emit('start');
this.changes = new Changes({
db: this.skim,
since: this.since,
inactivity_ms: this.inactivity_ms
});
this.changes.on('error', this.emit.bind(this, 'error'));
this.changes.on('retry', this.emit.bind(this, 'retry'));
this.changes.on('pause', this.emit.bind(this, 'pause'))
this.changes.on('resume', this.emit.bind(this, 'resume'));
this.changes.pipe(this);
};
EventSource.prototype._write = function (change, enc, callback) {
this._callback = callback;
if(!change.id) {
return;
}
this.since = change.seq;
this.emit('change', change);
//
// We don't REALLY care about design but in the future we
// do need the rewrites element. Might as well just store this separately
// though.
//
if (/^_design/.test(change.id)) {
return this.resume();
}
return change.deleted
? this.delete(change)
: this.getDoc(change);
};
EventSource.prototype.delete = function (change) {
//
// Not implemented yet
//
this.resume();
};
EventSource.prototype.getDoc = function (change) {
var q = '?revs=true&att_encoding_info=true';
var opts = url.parse(this.skim + '/' + change.id + q);
opts.method = 'GET';
opts.agent = false;
opts.headers = {
'content-type': 'application/json',
'connection': 'close'
};
var req = http.get(opts);
//
// TODO: Implement generic retries for ALL errors, this is especially
// important when it comes to attachments because we must ENSURE we fetch
// them
//
req.on('error', this.emit.bind(this, 'error'));
req.on('response', parse(this.onGet.bind(this, change)));
};
EventSource.prototype.onGet = function (change, err, doc, res) {
if (err) {
return this.emit('error', err);
}
change.doc = doc;
return isUnpublished(doc)
? this.unpublished(change)
: this.split(change);
};
//
// Make stubs for unpublished docs
//
EventSource.prototype.unpublished = function (change) {
var doc = change.doc;
//
// We are going to do some bullshit versions here based on the time records
//
var vDocs = Object.keys(doc.time)
.filter(function (key) {
return key != 'modified' && key != 'created';
}).reduce(function (acc, v) {
var d = acc[v] = {};
d._id = doc._id + '@' + v;
d.name = doc.name;
d.time = doc.time[v] || null;
// this isn't totally correct but should be OK for now
d.maintainers = doc.time.unpublished.maintainers;
return acc;
}, {}
);
var versions = Object.keys(vDocs);
//
// Skip when there are no versions to iterate through
//
if (!versions.length) {
return this.resume();
}
change.count = versions.length;
versions.forEach(function (v) {
this.put(change, vDoc[v]);
}, this);
};
//
// We simply just want to put a doc into the database here
//
EventSource.prototype.put = function (change, version) {
var id = encodeURIComponent(version._id);
var opts = url.parse(this.eventSource + '/' + id);
opts.method = 'PUT';
opts.agent = false;
opts.headers = {
'content-type': 'application/json',
'connection': 'close'
};
var payload = new Buffer(JSON.stringify(version), 'utf8');
var req = http.request(opts);
req.on('error', this.emit.bind(this, 'error'));
req.on('response', parse(this.onPutRes.bind(this, change, version)));
req.write(payload);
req.end();
};
//
// Iterate through document versions and split it into separate documents to
// insert into the database
//
EventSource.prototype.split = function (change) {
//
// TODO: handle diffing which versions we need to fetch instead of assuming
// all
//
var doc = change.doc;
var versions = Object.keys(doc.versions);
var tmp = path.resolve(this.tmp, change.id + '-' + change.seq);
//
// We don't care if it has no versions so skip it
//
if (!versions.length) {
return this.resume();
}
//
// Setup count for how many iterations to expect
//
change.count = versions.length;
//
// TODO: Handle stars
//
// TODO: check if it exists in database
// First iteration we are just going to populate this
// so we have data to write some views with
//
mkdirp(tmp, function (err) {
if (err) {
return this.emit('error', err);
}
versions.forEach(this.fetchAtt.bind(this, change))
}.bind(this));
};
//
// Fetch the attachment for the specified version that we are iterating through
//
EventSource.prototype.fetchAtt = function (change, v) {
var doc = change.doc;
var vDoc = doc.versions[v];
var reg = url.parse(vDoc.dist.tarball);
//
// May need to specify registry depending on the situation which is the
// direct url to whatever tarball service
//
if (this.registry) {
var p = '/' + change.id + '/-/' + path.basename(reg.pathname)
reg = url.parse(this.registry + p)
}
reg.method = 'GET';
reg.agent = false;
reg.headers = {
'user-agent': this.ua,
'connection': 'close'
};
var req = http.request(reg);
req.on('error', this.emit.bind(this, 'error'));
req.on('response', this.onAttRes.bind(this, change, v));
req.end();
};
//
// Check the files and make sure they match what the document says while
// streaming them to the file system
//
EventSource.prototype.onAttRes = function (change, v, res) {
var doc = change.doc;
var vDoc = doc.versions[v];
var att = vDoc.dist.tarball;
var sum = vDoc.dist.shasum;
var filename = change.id + '-' + v + '.tgz';
var file = path.join(this.tmp, change.id + '-' + change.seq, filename);
if (res.statusCode != 200) {
//
// TODO: Retry
//
return this.missingLog
? fs.appendFile(this.missingLog, att + '\n', this.isFinished.bind(this, change))
: this.emit('error', new Error('Unable to properly fetch attachment ' + filename));
}
//
// Make them streams for some crazy pipe action
//
var fileStream = fs.createWriteStream(file);
var sha = crypto.createHash('sha1');
var shaOk = false;
var errState = null;
sha.on('data', function (data) {
data = data.toString('hex');
if (data === sum) {
shaOk = true;
}
});
if (!res.headers['content-length']) {
var counter = new Counter();
res.pipe(counter);
}
res.pipe(sha);
res.pipe(fileStream);
//
// Add some extra info to the error obj if this happens and emit
// TODO: This shouldn't really happen but we should refetch if this is the
// case
//
fileStream.on('error', function (err) {
err.change = change;
err.version = v;
err.path = file;
err.url = att;
errState = err;
this.emit('error', err);
}.bind(this));
//
// See if we to stop here because the stream errored
//
fileStream.on('close', function () {
if (errState || !shaOk) {
//
// Hmm so this will definitely be hit maybe do the refetch here
// for both cases if the sha is not the same AND if we failed to write to
// the filesystem
//
// just gonna throw an error for now cause shit is fucked
//
return this.emit('error', new Error('Sha did not match or we are in a bad state ' + errState));
}
//
// Remark: I guess keep the name of the attachment the same as before?
// **note** at least we know that we can form this name from the name
// property and the version property
//
var name = path.basename(filename);
this.emit('download', name);
//
// Hmm should these be the same urls as before? I think so
//
var newAtt = this.pubEventSource + '/' + change.id +
'/' + change.id + '-' + v + '.tgz';
//
// Remark: Setup the new document that we are forming with any necessary
// attributes from the old behemoth doc.
//
vDoc.dist.tarball = newAtt
vDoc.time = doc.time && doc.time[v] || null;
//
// Attach the default readme to the version document so we ensure
// each version has one at least
//
vDoc.readmeFilename = vDoc.readmeFilename || doc.readmeFilename;
vDoc.readme = vDoc.readme || doc.readme;
//
// Remark: So these tricksy little underscore based keys can cause problems
// for couchDB as it uses them internally. In reality we shouldnt use these
// AT ALL but lets see with what we can get away with prefixing.
//
vDoc = Object.keys(vDoc).reduce(function (doc, key) {
if (key !== '_id' && /^_/.test(key)) {
var k = this._prefix + key;
doc[k] = vDoc[key];
return doc;
}
doc[key] = vDoc[key];
return doc;
}.bind(this), {});
//
// Ensure we get content length to append to the data structure we use to
// send the actual request.
//
var cl = res.headers['content-length']
? +res.headers['content-length']
: counter.bytes;
//
// Create the attachment here and form the final doc when we do a PUT
// as we need the attachment values to do all the crazy boundary shit
//
var attachment = {
length: cl,
follows: true,
// We make an assumption here but this should be safe (in theory);
content_type: res.headers['content-type'] || 'application/octet-stream'
};
this.putMultiPart(change, vDoc, name, attachment);
}.bind(this));
};
//
// Insert the single document with its one attachment as a single
// multipart/related request so it is much more efficient
//
EventSource.prototype.putMultiPart = function (change, vDoc, name, att) {
var id = encodeURIComponent(vDoc._id);
var file = path.join(this.tmp, change.id + '-' + change.seq, name);
//
// Oh yea add attachment shit to the actual vDoc
//
vDoc._attachments = {};
vDoc._attachments[name] = att;
//
// Start setting up request related things;
//
var opts = url.parse(this.eventSource + '/' + id);
opts.method = 'PUT';
opts.agent = false;
opts.headers = {
'user-agent': this.ua,
'content-type': 'multipart/related;boundary="' + this.boundary + '"',
'connection': 'close'
};
//
// Make a doc buffer to write to the stream
//
var doc = new Buffer(JSON.stringify(vDoc), 'utf8');
//
// Ridiculous boundary strings that we need to separate the pieces of our request with.
//
var docBoundary = '--' + this.boundary + '\r\n' +
'content-type: application/json\r\n' +
'content-length: ' + doc.length + '\r\n\r\n';
var attBoundary = '\r\n--' + this.boundary + '\r\n' +
'content-length: ' + att.length + '\r\n' +
'content-disposition: attachment; filename=' +
JSON.stringify(name) + '\r\n' +
'content-type: ' + att.content_type + '\r\n\r\n';
var finalBoundary = '\r\n--' + this.boundary + '--';
//
// Add all the length values so we know what we are dealing with here
//
opts.headers['content-length'] = doc.length + att.length
+ docBoundary.length + attBoundary.length + finalBoundary.length;
//
// Create that request for the big PUT!
//
var req = http.request(opts);
req.on('error', this.emit.bind(this, 'error'));
req.on('response', parse(this.onPutRes.bind(this, change, vDoc)));
//
// Start the boundary -> data chain. Pipe some shit, then write the last
// boundary
//
req.write(docBoundary, 'ascii');
req.write(doc);
req.write(attBoundary, 'ascii');
//
// Setup the readStream and finish it off with a pipe!
//
var rs = fs.createReadStream(file);
rs.on('error', this.emit.bind(this, 'error'));
//
// Since we technically need to write a last boundary after the stream,
// we listen for end and do that here
//
rs.on('end', function () {
req.write(finalBoundary, 'ascii');
req.end();
}.bind(this));
//
// Don't auto end so that we can write the final boundary
//
rs.pipe(req, { end: false });
};
//
// Check for errors and such after we attempt our crazy multipart/related PUT
//
EventSource.prototype.onPutRes = function (change, doc, err, data, res) {
if (err && err.statusCode != 409) {
return this.emit('error', err);
}
//
// Jut ignore because it means it was inserted and we crashed for whatever
// reason
// TODO: Don't let this case exist and use retries and record skip failures
//
if (res.statusCode == 409) {
this.emit('skip', err.message);
}
else {
this.emit('put', doc, data);
}
this.isFinished(change)
};
//
// Check if we are finished with our iteration since we are doing `n` PUTs
// based on the number of versions each document has
//
EventSource.prototype.isFinished = function (change) {
if (--change.count === 0) {
rimraf(this.tmp + '/' + change.id + '-' + change.seq, noop);
return this.resume();
}
};
//
// Since we assume a concurrency of 1, on each resume save the seq that we just
// inserted into the database so we know where to start from if something
// terrible happens
//
EventSource.prototype.resume = function () {
this.seqFile.save(this.since);
this._callback();
};
function isUnpublished(doc) {
return doc
&& doc.time
&& doc.time.unpublished;
}