In the last chapter we finished a simple file server with similar basic functionality
\nto Apache. That being said though, we have a long function to execute a very specific
\ntask. It would be ideal if we could create a module to separate that function to
\nmake our clean cleaner and shorter. The good news is that it’s entirely possible.
\nIf you recall, we already installed two libraries into our project, “mime” and
\n“async”, and the better news is that we can create our own libraries and modules
\nto be installed in the same way.<\/p>\n
We can copy and paste our function into it’s own source file for handling files.<\/p>\n
File: handle-file.js<\/p>\n
\"use strict\";\n\nconst fs = require(\"fs\");\nconst mime = require(\"mime\");\nconst async = require(\"async\");\n\nconst PATH = \"public\";\n\nmodule.exports = function (req, res) {\n\n fs.stat(PATH + req.url, function( err, stats ) {\n if( err ) {\n res.writeHead(404, {\"Content-Type\" : \"text\/plain\"});\n return res.end(\"File Not Found\");\n }\n\n if( stats.isFile() ) {\n\n res.writeHead(200, {\"Content-Type\" : mime.lookup(req.url) });\n let stream = fs.createReadStream(PATH + req.url);\n stream.pipe(res);\n\n } else if( stats.isDirectory() ) {\n\n if(req.url[req.url.length - 1] !== \"\/\") {\n\n res.writeHead(302, { \"Location\" : req.url + \"\/\" });\n return res.end();\n\n }\n\n fs.readdir(PATH + req.url, function(err, files) {\n if(err) {\n throw err;\n }\n\n if(files.indexOf(\"index.html\") !== -1) {\n\n res.writeHead(200, {\"Content-Type\" : \"text\/html\" });\n let stream = fs.createReadStream(PATH + req.url + \"index.html\");\n stream.pipe(res);\n return;\n\n }\n\n let file_list = [];\n let dir_list = [];\n\n async.eachSeries(files, function(file, nextFile) {\n\n fs.stat(PATH + req.url + file, function( err, stats ) {\n if(err) {\n throw err;\n }\n\n if(stats.isFile()) {\n\n file_list.push(file);\n\n } else if(stats.isDirectory()) {\n\n if(file !== \".\") {\n dir_list.push(file);\n }\n\n }\n\n nextFile();\n });\n\n }, function() {\n\n file_list.sort();\n dir_list.sort();\n\n res.writeHead(200, {\"Content-Type\" : \"text\/html\" });\n res.write(\"<!DOCTYPE HTML>\");\n res.write(\"<html>\");\n res.write(\"<head>\");\n res.write(\"<meta charset=\\\"utf-8\\\">\");\n res.write(\"<title>Index<\/title>\");\n res.write(\"<\/head>\");\n res.write(\"<body>\");\n res.write(\"<h1>\"+req.url+\"<\/h1>\");\n res.write(\"<ul>\");\n\n dir_list.forEach(function(dir){\n\n res.write(\"<li>\");\n res.write(\"<a href=\\\"\" + dir + \"\/\\\">\");\n res.write(dir + \"\/\");\n res.write(\"<\/a>\");\n res.write(\"<\/li>\");\n\n });\n\n file_list.forEach(function(file){\n\n res.write(\"<li>\");\n res.write(\"<a href=\\\"\" + file + \"\\\">\");\n res.write(file);\n res.write(\"<\/a>\");\n res.write(\"<\/li>\");\n\n });\n\n res.write(\"<\/ul>\");\n res.write(\"<\/body>\");\n res.end(\"<\/html>\");\n\n });\n\n });\n\n } else {\n\n res.writeHead(404, {\"Content-Type\" : \"text\/plain\"});\n return res.end(\"File Not Found\");\n\n }\n\n });\n\n}\n<\/pre>\nNext we can run “`$ npm init“` in the directory we created our source file in
\nto create a package.json file describing the source file we created for Node to
\ninclude in other files. We will be asked to answer a few answers about our package
\nbut the result should look similar to the following.<\/p>\n
File: package.json<\/p>\n
{\n \"name\": \"handle-file\",\n \"version\": \"1.0.0\",\n \"description\": \"A simple function for serving static files from a \\\"public\\\" folder\",\n \"main\": \"handle-file.js\",\n \"scripts\": {\n \"test\": \"echo \\\"Error: no test specified\\\" && exit 1\"\n },\n \"keywords\": [\n \"handle\",\n \"file\",\n \"server\",\n \"http\"\n ],\n \"author\": \"Benjamin Collins\",\n \"license\": \"MIT\"\n}\n<\/pre>\nBut there’s one thing missing. Since we’re using the libraries “mime” and “async”
\n, we need to include that information into our package.json file. That will be
\ndone automatically is we run the command:<\/p>\n
$ npm install async mime --save\n<\/pre>\nAfter doing that, our package.json should shoud now have a “dependencies” attribute.<\/p>\n
\"dependencies\": {\n \"async\": \"^2.3.0\",\n \"mime\": \"^1.3.4\"\n}\n<\/pre>\nNow we’re almost ready to publish. Before doing so, we should create a “readme.md”
\nexplaining our code and what it does so other people can use it. Plus it’s always
\nhelpful if we forget. If you don’t already, you can create an account on
\nhttps:\/\/www.npmjs.com. Once you’ve done so, you can login via the command line
\nwith:<\/p>\n
$ npm adduser\nUsername: [ username-here ]\nPassword: [ password-here ]\nEmail: (this IS public) your-email@domain.com\nLogged in as username-here on https:\/\/registry.npmjs.org\/.\n<\/pre>\nThen we can publish our created module with:<\/p>\n
$ npm publish .\n<\/pre>\nWe can now include our function to handle files like we did with “mime” and “async”
\nwith:<\/p>\n
$ npm install file-handle\n<\/pre>\nAnd our final code for this chapter is much shorter, looks like the following:<\/p>\n
File: file_server.js<\/p>\n
\"use strict\";\n\nconst http = require(\"http\");\nconst handleFile = require(\"handle-file\");\n\nconst server = http.createServer();\nserver.on(\"request\", handleRequest);\nserver.listen(8080, handleListen);\n\nfunction handleRequest(req, res) {\n\n handleFile(req, res);\n\n}\n\nfunction handleListen() {\n\n console.log(\"Server is listening on port 8080\");\n\n}\n<\/pre>\nAnd with that we’ve learned how to make modules and cleaned up our code. With a
\nbasic file server and cleaner code we are going to focus more on interaction with
\nclient web browsers in the next chapter.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the previous chapter, we implemented the functionality of a directory index where all of the files in a directory would be listed. As a result of that our code started to get long and messy, so in this chapter we introduce modules to implement specific functionality to organize our code.<\/p>\n","protected":false},"author":1,"featured_media":249,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false},"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/posts\/265"}],"collection":[{"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=265"}],"version-history":[{"count":7,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/posts\/265\/revisions"}],"predecessor-version":[{"id":273,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/posts\/265\/revisions\/273"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=\/wp\/v2\/media\/249"}],"wp:attachment":[{"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=265"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=265"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.wsd.sh\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}