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node-red/red/runtime/storage/localfilesystem/util.js
2018-05-01 12:28:15 +01:00

109 lines
4.1 KiB
JavaScript

/**
* Copyright JS Foundation and other contributors, http://js.foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
**/
var fs = require('fs-extra');
var when = require('when');
var nodeFn = require('when/node/function');
var log = require("../../../util").log; // TODO: separate module
function parseJSON(data) {
if (data.charCodeAt(0) === 0xFEFF) {
data = data.slice(1)
}
return JSON.parse(data);
}
function readFile(path,backupPath,emptyResponse,type) {
return when.promise(function(resolve) {
fs.readFile(path,'utf8',function(err,data) {
if (!err) {
if (data.length === 0) {
log.warn(log._("storage.localfilesystem.empty",{type:type}));
try {
var backupStat = fs.statSync(backupPath);
if (backupStat.size === 0) {
// Empty flows, empty backup - return empty flow
return resolve(emptyResponse);
}
// Empty flows, restore backup
log.warn(log._("storage.localfilesystem.restore",{path:backupPath,type:type}));
fs.copy(backupPath,path,function(backupCopyErr) {
if (backupCopyErr) {
// Restore backup failed
log.warn(log._("storage.localfilesystem.restore-fail",{message:backupCopyErr.toString(),type:type}));
resolve([]);
} else {
// Loop back in to load the restored backup
resolve(readFile(path,backupPath,emptyResponse,type));
}
});
return;
} catch(backupStatErr) {
// Empty flow file, no back-up file
return resolve(emptyResponse);
}
}
try {
return resolve(parseJSON(data));
} catch(parseErr) {
log.warn(log._("storage.localfilesystem.invalid",{type:type}));
return resolve(emptyResponse);
}
} else {
if (type === 'flow') {
log.info(log._("storage.localfilesystem.create",{type:type}));
}
resolve(emptyResponse);
}
});
});
}
module.exports = {
/**
* Write content to a file using UTF8 encoding.
* This forces a fsync before completing to ensure
* the write hits disk.
*/
writeFile: function(path,content,backupPath) {
if (backupPath) {
try {
fs.renameSync(path,backupPath);
} catch(err) {
}
}
return when.promise(function(resolve,reject) {
var stream = fs.createWriteStream(path);
stream.on('open',function(fd) {
stream.write(content,'utf8',function() {
fs.fsync(fd,function(err) {
if (err) {
log.warn(log._("storage.localfilesystem.fsync-fail",{path: path, message: err.toString()}));
}
stream.end(resolve);
});
});
});
stream.on('error',function(err) {
reject(err);
});
});
},
readFile: readFile,
parseJSON: parseJSON
}