I've used the following code to call two modules, but the invoke action is called before the validate file (I saw in debug). What I should do to verify that validateFile is called before appHandler.invokeAction? Should I use a promise?
var validator = require('../uti/valid').validateFile();
var appHandler = require('../contr/Handler');
appHandler.invokeAction(req, res);
Update
this is the validate file code
var called = false;
var glob = require('glob'),
fs = require('fs');
module.exports = {
validateFile: function () {
glob("myfolder/*.json", function (err, files) {
var stack = [];
files.forEach(function (file) {
fs.readFile(file, 'utf8', function (err, data) { // Read each file
if (err) {
console.log("cannot read the file", err);
}
var obj = JSON.parse(data);
obj.action.forEach(function (crud) {
for (var k in crud) {
if (_inArray(crud[k].path, stack)) {
console.log("duplicate founded!" + crud[k].path);
break;
}
stack.push(crud[k].path);
}
})
});
});
});
}
};
Because glob and fs.readFile are async functions and appHandler.invokeAction is invoked during i/o from disk.
Promise is a good solution to solve this but an old school callback could do the job.
validator.validateFile().then(function() {
appHandler.invokeAction(req, res);
});
and for validate
var Promise = require("bluebird"), // not required if you are using iojs or running node with `--harmony`
glob = require('mz/glob'),
fs = require('mz/fs');
module.exports = {
validateFile: function () {
return glob("myfolder/*.json").then(function(files) {
return Promise.all(files.map(function(file) {
// will return an array of promises, if any of them
// is rejected, validateFile promise will be rejected
return fs.readFile(file).then(function (content) {
// throw new Error(''); if content is not valid
});
}));
})
}
};
If you want working with promise mz could help :)
As the fs.fileRead is async, you should put the code that you want to execute after validateFile to its callback.
The origin could be:
var validator = require('../uti/valid').validateFile();
var appHandler = require('../contr/Handler');
// create a new function that when execute, will call appHandler.invokeAction with req and res given to its arguments.
validator.validateFile(appHandler.invokeAction.bind(null, req, res));
The validator part should be:
var called = false;
var glob = require('glob'),
fs = require('fs');
module.exports = {
validateFile: function (callback) {
glob("myfolder/*.json", function (err, files) {
var stack = [];
// Use it to decide whether all files processed or not.
var filesToLoad = files.length;
files.forEach(function (file) {
fs.readFile(file, 'utf8', function (err, data) { // Read each file
--filesToLoad;
if (err) {
console.log("cannot read the file", err);
// If the invoke action doesn't depend on the result. You may want to call it here too.
}
var obj = JSON.parse(data);
obj.action.forEach(function (crud) {
for (var k in crud) {
if (_inArray(crud[k].path, stack)) {
console.log("duplicate founded!" + crud[k].path);
break;
}
stack.push(crud[k].path);
}
})
// Only called the callback after all files processed.
if (filesToLoad === 0) {
callback();
}
});
});
});
}
};
Edit: Thanks for Bergi's remind that there's the files are an array and you have to call the callback when all files is processed, so we have to further use a variable to decide how many files are not processed yet.
