I am working on creating my first Node.js module, and am having a difficult time trying to decide the best way to handle this. What is the recommended method for receiving paths to files to my module as input by the user? How can I then resolve where that is? Where the user called my module and the location of my running code are in two different places.
Let's take this a step further. Let's say a user has a JSON config file with an array of these paths (in config/settings.json):
{
"paths": [
"../path1",
"path2",
"/path/to/path3",
"~/path4"
]
}
Now obviously these paths are relative to the config file, not any executing code. This feels wrong, as now my method must accept the __dirname, the path of the config file relative to __dirname, etc.
var mymodule = require('mine');
mymodule(__dirname, './config/settings.json');
Any files I read from the config must then be based on the location of this config file. This feels weird. Suggestions?
From FileUtils source:
var updateFileProperties = function (file, path){
file._path = null;
file._usablePath = null;
file._isAbsolute = false;
if (path === undefined || path === null) return;
path = PATH.normalize (path);
var index = path.indexOf (":") + 1;
var windowsRoot = path.substring (0, index);
path = path.substring (index);
//https://github.com/joyent/node/issues/3066
if (path[0] === "/" && path[1] === "/"){
path = path.replace (/[\/]/g, "\\");
path = path.substring (0, path.length - 1);
}
file._isAbsolute = path[0] === SLASH;
file._path = windowsRoot + path;
file._usablePath = file._isAbsolute ? file._path : (windowsRoot + PATH.join (file._relative, path));
};
var File = function (path){
var main = process.mainModule.filename;
var cwd = main.substring (0, main.lastIndexOf (SLASH));
var relative = PATH.relative (process.cwd (), cwd);
this._relative = relative;
//...omitted
updateFileProperties (this, path);
};
This piece of code resolves the relative path problem.
_usablePath contains the real path. The "." path will be the directory where the main file is located. No matter how is called, it will point to the expected directory.
You can test the functions printing what the new File (<path>).getPath () returns.
I would avoid complexity and go for absolute paths only. Most users do __dirname + '../relativepath' anyways. ( at least that's what I do ).
Related
Is there any clean way to check if a path is a file or directory?
Currently I am using this:
exports.isDirectory = (dirPath) => {
return fs.lstatSync(dirPath).isDirectory()
}
But my problem here is that if dirPath does not exist yet, then lstatSync gives out an error.
Then I also tried:
exports.getFileName = (filePath) => {
return filePath.split(/[\\\/]/).pop()
}
exports.isDirectory = (dirPath) => {
return exports.getFileName(dirPath) === ''
}
And call:
const home = require('os').homedir()
const sampleLoc = path.join(home, '/.folder/another'))
isDirectory(sampleLoc)
But it only basically thinks another is the filename and returns false on isDirectory.
Can't really check for the presence of . (like an extension of a file name) since my folders can have dots anywhere on its name.
How can I check if the given path is for a file or directory? (considering it does not exist yet at the point of checking)?
Help!
I tried many ways available in different sites to unzip the downloaded zipped folder and found the below one is simplest way.However, am facing the below issue.Please help me resolve this :
const extract = require('extract-zip');
const path = require('path');
unzip=async function(){
let source = "Downloads/sample.zip";
let destination = "Downloads/";
let sP = path.resolve(source);
console.log("Source path : " +sP);
let dP = path.resolve(destination);
console.log("Destination path : " +dP);
await extract(sP, { dir: dP });
console.log('Extraction complete');
}
Output :
Source path : /Users/myName/Documents/framework/Downloads/sample.zip
Destination path :/Users/myName/Documents/framework/Downloads
.
.
Error: absolute path://sample/
The resolved path should be relative to the path of the directory where the code is being executed.
Replace
let source = '../../Downloads/sample.zip
let destination = '../../Downloads
let sP = path.resolve(source);
let dP = path.resolve(destination);
The problem is the .zip file itself starting with //. Extract-zip uses yauzl which throws an exception if it's an absolute path:
https://github.com/thejoshwolfe/yauzl/issues/135
I am attempting to do a file search based off array of file names and root directory. I found some file search snips online that seem to work when I am finding just 1 single file, but it will not work when there is more than 1 file specified. Below is the snippet:
const fs = require('fs');
const path = require('path');
var dir = '<SOME ROOT DIRECTORY>';
var file = 'Hello_World.txt'
var fileArr = ['Hello_World.txt', 'Hello_World2.txt', 'Hello_World3.txt'];
const findFile = function (dir, pattern) {
var results = [];
fs.readdirSync(dir).forEach(function (dirInner) {
dirInner = path.resolve(dir, dirInner);
var stat = fs.statSync(dirInner);
if (stat.isDirectory()) {
results = results.concat(findFile(dirInner, pattern));
}
if (stat.isFile() && dirInner.endsWith(pattern)) {
results.push(dirInner);
}
});
return results;
};
console.log(findFile(dir, file));
Any thoughts on how I can get this working with an array rather than just a single file string?
Doing the following seems to be working, but didn't know if there were other ways to do this which may be simpler:
newFileArr = [];
fileArr.forEach((file => {
//findFile(dir, file).toString();
console.log(findFile(dir, file).toString());
}));
The only thing that needs to change is the condition to determine if an individual filepath meets the search criteria. In the code you've posted, it looks like dirInner.endsWith(pattern), which says "does the filepath end with the given pattern?"
We want to change that to say "does the filepath end with any of the given patterns?" And closer to how the code will look, we can rephrase that as "Can we find a given pattern such that the filepath ends with that pattern?"
Let's rename pattern to patterns. Then we can simple replace dirInner.endsWith(patterns) with patterns.some(pattern => dirInner.endsWith(pattern))
I am writing a Webpack loader for Pug files. It loads all the dependent images referenced in the Pug file, uses file-loader to copy them to the appropriate directory, and replaces require() calls in the Pug file with the URLs of the resultant file.
I am trying to add functionality to allow for data URLs to be interpolated into the Pug file in lieu of file URLs. I am using this.loadModule() to execute file-loader now.
This function takes a callback as an argument. One of the args passed to this callback contains the result of url-loader, the data URL. So, I need this to write into the Pug file that should be output.
The problem is, the entire loader finishes running before that callback ever runs. So, anything I do with the data in there doesn't end up in the final file. The overall structure of my program looks like this:
module.exports = function pugDepLoader(inputFile) {
/* Setting up various constants and variables. */
/* A while() loop that continually tests inputFile with a
regex to find require() statements.
It creates a copy of inputFile called outputFile,
which it iterates over again and again,
replacing require() statements with file paths
one at a time.
The call to this.loadModule() is within this while() loop. */
/* End of while() loop */
/* Return outputFile to Webpack, which is now a
string with the Pug file, but with the
require() statements replaced with
file paths.
This is meant to be fed to file-loader to
get written out to disc. */
}
That return statement at the end will get called repeatedly before this.loadModule()'s callback ever runs once, as I have discovered with debugging statements. I need to be able to get that data URL that is provided within the callback into outputFile before I return it, so that it will end up in the file that is ultimately written to disc.
Entire source code follows:
module.exports = function pugDepLoader(inputFile) {
const fs = require('fs');
const path = require('path');
const loaderUtils = require('loader-utils');
var options = loaderUtils.getOptions(this);
//This option is required. It specifies
//the path to the root of the Pug file's
//dependencies relative to the location
//of the Pug files.
var contextualRoot;
if(!options || !options.hasOwnProperty('contextualRoot')) {
throw new Error('You must specify a contextual root');
}
else {
contextualRoot = options.contextualRoot;
//Ensure there is a trailing slash.
if(contextualRoot[contextualRoot.length-1] !== '/') {
contextualRoot = contextualRoot + '/';
}
}
//Determines whether paths should begin with
//a leading slash. Useful for Express.js
//compatibility.
if(!options.hasOwnProperty('absolute')) {
options.absolute = false;
}
//Set up regex to search for require() statements
const reqRE = new RegExp(/require\(/, 'g');
//outputFile will be returned containing the
//appropriately processed Pug
var outputFile = inputFile.slice();
//We need to execute reqRE once to kick things
//off, and we need to save it to a variable
//because we need information from it.
let regexResult = reqRE.exec(inputFile);
//regexResult will be null when there
//are no more matches to be found in
//the file.
while(regexResult != null) {
//pathStartIndex is the beginning of
//the path to the required file.
//We add 1 to skip the opening
//single quote.
let pathStartIndex = reqRE.lastIndex+1;
//We require the path to be wrapped in
//single quotes, so that we can easily
//be certain about where the require
//statement ends.
if(inputFile[reqRE.lastIndex] !== "'") {
console.log('FATAL ERROR: File path must be wrapped in single quotes!');
break;
}
//inputPath will hold the actual file path itself.
let inputPath = inputFile.slice(pathStartIndex, inputFile.indexOf("'", pathStartIndex));
//pathArray is used to split the
//path so we can easily extract
//the file name and path
//separately.
let pathArray = inputPath.split('/');
//Just the file name, with extension.
let fileName = pathArray.pop();
//outputPath will define what path should be
//written into the output Pug file.
//The user may optionally specify a
//custom output path.
let outputPath;
if(options.outputPath) {
outputPath = options.outputPath;
}
else {
outputPath = pathArray.join('/');
}
//Ensure a trailing slash.
if(outputPath[outputPath.length-1] !== '/') {
outputPath = (outputPath + '/');
}
//reqStart holds the index of the letter
//"r" in require(), so that we can remove
//the require() call and replace it
//with the file path.
let reqStart = inputFile.indexOf('require', regexResult.index);
//reqStmt is the require() statement in
//full. This will be used with replace()
//to replace the require() call with a
//file path in the output file.
let reqStmt = inputFile.slice(reqStart, inputFile.indexOf('"', pathStartIndex));
//The final file path, with file name.
//This will be written into the output
//Pug file in place of the require()
//calls.
let filePath = outputPath + fileName;
if(options.absolute && filePath[0] !== '/') {
if(filePath[0] === '.' && filePath[1] === '/') {
filePath = filePath.slice(1);
}
else {
filePath = '/' + filePath;
}
}
else if(!options.absolute && filePath[0] === '/') {
filePath = filePath.slice(1);
}
this.loadModule(contextualRoot + inputPath, (err, res, srcmap, module) => {
if(err) {
console.log(err);
}
if(new RegExp(/data:image/).test(res)) {
filePath = res.slice(res.indexOf('data:image'), res.lastIndexOf('"'));
}
});
//This takes care of require() calls
//inside of url() CSS functions,
//such as are used to declare
//background images inline.
//If the word "require" is
//preceeded by a single quote,
//it is within a url() function,
//and so we add appropriate closure
//for that function to the end of
//the path.
if(inputFile[reqStart-1] === "'") {
filePath = filePath + "');";
}
//Write the output.
outputFile = outputFile.replace(reqStmt, filePath);
//Run the next iteration of the regex search.
regexResult = reqRE.exec(inputFile);
}
//Return output as a string to Webpack.
return outputFile;
}
How can I tell in JavaScript what path separator is used in the OS where the script is running?
Use path module in node.js returns the platform-specific file separator.
example
path.sep // on *nix evaluates to a string equal to "/"
Edit: As per Sebas's comment below, to use this, you need to add this at the top of your js file:
const path = require('path')
Afair you can always use / as a path separator, even on Windows.
Quote from http://bytes.com/forum/thread23123.html:
So, the situation can be summed up
rather simply:
All DOS services since DOS 2.0 and all Windows APIs accept either forward
slash or backslash. Always have.
None of the standard command shells (CMD or COMMAND) will accept forward
slashes. Even the "cd ./tmp" example
given in a previous post fails.
The Correct Answer
Yes all OS's accept CD ../ or CD ..\ or CD .. regardless of how you pass in separators. But what about reading a path back. How would you know if its say, a 'windows' path, with ' ' and \ allowed.
The Obvious 'Duh!' Question
What happens when you depend on, for example, the installation directory %PROGRAM_FILES% (x86)\Notepad++. Take the following example.
var fs = require('fs'); // file system module
var targetDir = 'C:\Program Files (x86)\Notepad++'; // target installer dir
// read all files in the directory
fs.readdir(targetDir, function(err, files) {
if(!err){
for(var i = 0; i < files.length; ++i){
var currFile = files[i];
console.log(currFile);
// ex output: 'C:\Program Files (x86)\Notepad++\notepad++.exe'
// attempt to print the parent directory of currFile
var fileDir = getDir(currFile);
console.log(fileDir);
// output is empty string, ''...what!?
}
}
});
function getDir(filePath){
if(filePath !== '' && filePath != null){
// this will fail on Windows, and work on Others
return filePath.substring(0, filePath.lastIndexOf('/') + 1);
}
}
What happened!?
targetDir is being set to a substring between the indices 0, and 0 (indexOf('/') is -1 in C:\Program Files\Notepad\Notepad++.exe), resulting in the empty string.
The Solution...
This includes code from the following post: How do I determine the current operating system with Node.js
myGlobals = { isWin: false, isOsX:false, isNix:false };
Server side detection of OS.
// this var could likely a global or available to all parts of your app
if(/^win/.test(process.platform)) { myGlobals.isWin=true; }
else if(process.platform === 'darwin'){ myGlobals.isOsX=true; }
else if(process.platform === 'linux') { myGlobals.isNix=true; }
Browser side detection of OS
var appVer = navigator.appVersion;
if (appVer.indexOf("Win")!=-1) myGlobals.isWin = true;
else if (appVer.indexOf("Mac")!=-1) myGlobals.isOsX = true;
else if (appVer.indexOf("X11")!=-1) myGlobals.isNix = true;
else if (appVer.indexOf("Linux")!=-1) myGlobals.isNix = true;
Helper Function to get the separator
function getPathSeparator(){
if(myGlobals.isWin){
return '\\';
}
else if(myGlobals.isOsx || myGlobals.isNix){
return '/';
}
// default to *nix system.
return '/';
}
// modifying our getDir method from above...
Helper function to get the parent directory (cross platform)
function getDir(filePath){
if(filePath !== '' && filePath != null){
// this will fail on Windows, and work on Others
return filePath.substring(0, filePath.lastIndexOf(getPathSeparator()) + 1);
}
}
getDir() must be intelligent enough to know which its looking for.
You can get even really slick and check for both if the user is inputting a path via command line, etc.
// in the body of getDir() ...
var sepIndex = filePath.lastIndexOf('/');
if(sepIndex == -1){
sepIndex = filePath.lastIndexOf('\\');
}
// include the trailing separator
return filePath.substring(0, sepIndex+1);
You can also use 'path' module and path.sep as stated above, if you want to load a module to do this simple of a task. Personally, i think it sufficient to just check the information from the process that is already available to you.
var path = require('path');
var fileSep = path.sep; // returns '\\' on windows, '/' on *nix
And Thats All Folks!
As already answered here, you can find the OS specific path separator with path.sep to manually construct your path. But you can also let path.join do the job, which is my preferred solution when dealing with path constructions:
Example:
const path = require('path');
const directory = 'logs';
const file = 'data.json';
const path1 = `${directory}${path.sep}${file}`;
const path2 = path.join(directory, file);
console.log(path1); // Shows "logs\data.json" on Windows
console.log(path2); // Also shows "logs\data.json" on Windows
Just use "/", it works on all OS's as far as I know.