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cryptpad/storage/tasks.js

99 lines
2.7 KiB
JavaScript

var Fs = require("fs");
var Fse = require("fs-extra");
var Path = require("path");
var nacl = require("tweetnacl");
var nThen = require("nthen");
var Tasks = module.exports;
var encode = function (time, command, args) {
if (typeof(time) !== 'number') { return null; }
if (typeof(command) !== 'string') { return null; }
if (!Array.isArray(args)) { return [time, command]; }
return [time, command].concat(args);
};
var randomId = function () {
var bytes = Array.prototype.slice.call(nacl.randomBytes(16));
return bytes.map(function (b) {
var n = Number(b & 0xff).toString(16);
return n.length === 1? '0' + n: n;
}).join('');
};
var mkPath = function (env, id) {
return Path.join(env.root, id.slice(0, 2), id) + '.ndjson';
};
var getFreeId = function (env, cb, tries) {
if (tries > 5) { return void cb('ETOOMANYTRIES'); }
// generate a unique id
var id = randomId();
// derive a path from that id
var path = mkPath(env, id);
Fs.stat(path, function (err) {
if (err && err.code === "ENOENT") {
cb(void 0, id);
} else {
getFreeId(env, cb);
}
});
};
var write = function (env, task, cb) {
var str = JSON.stringify(task) + '\n';
var id = nacl.util.encodeBase64(nacl.hash(nacl.util.decodeUTF8(str))).replace(/\//g, '-');
var path = mkPath(env, id);
nThen(function (w) {
// check if the file already exists...
Fs.stat(path, w(function (err) {
if (err && err.code === 'ENOENT') { return; }
w.abort(); cb();
}));
}).nThen(function (w) {
// create the parent directory if it does not exist
var dir = id.slice(0, 2);
var dirpath = Path.join(env.root, dir);
Fse.mkdirp(dirpath, 0x1ff, w(function (err) {
if (err) {
return void cb(err);
}
}));
}).nThen(function () {
// write the file to the path
Fs.writeFile(mkPath(env, id), str, function (e) {
if (e) { return void cb(e); }
cb();
});
});
};
// TODO implement a standard API for removing tasks
// currently they are deleted manually in 'expire-channels.js'
// var remove = function (env, id, cb) { };
Tasks.create = function (config, cb) {
var env = {
root: config.taskPath || './tasks',
};
// make sure the path exists...
Fse.mkdirp(env.root, 0x1ff, function (err) {
if (err && err.code !== 'EEXIST') {
throw err;
}
cb(void 0, {
write: function (time, command, args, cb) {
var task = encode(time, command, args);
write(env, task, cb);
},
});
});
};