nodeschool.io 8
~~ HTTP COLLECT ~~
Write a program that performs an HTTP GET request to a URL provided to
you as the first command-line argument. Collect all data from the
server (not just the first "data" event) and then write two lines to
the console (stdout).
The first line you write should just be an integer representing the
number of characters received from the server and the second line
should contain the complete String of characters sent by the server.
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HINTS:
There are two approaches you can take to this problem:
1) Collect data across multiple "data" events and append the results
together prior to printing the output. Use the "end" event to
determine when the stream is finished and you can write the output.
2) Use a third-party package to abstract the difficulties involved in
collecting an entire stream of data. Two different packages provide a
useful API for solving this problem (there are likely more!):
`bl` (Buffer List) and `concat-stream`; take your pick!
http://npm.im/bl
http://npm.im/concat-stream
To install a Node package, use the Node Package Manager `npm`. Simply
type:
npm install bl
And it will download and install the latest version of the package
into a subdirectory named `node_modules`. Any package in this
subdirectory under your main program file can be loaded with the
`require` syntax without being prefixed by './':
var bl = require('bl')
Node will first look in the core modules and then in the
`node_modules` directory where the package is located.
If you don't have an Internet connection, simply make a `node_modules`
directory and copy the entire directory for the package you want to
use from inside the learnyounode installation directory:
C:\Users\dzhang\AppData\Roaming\npm\node_modules\learnyounode\node_modules\bl
C:\Users\dzhang\AppData\Roaming\npm\node_modules\learnyounode\node_modules\con
cat-stream
Both `bl` and `concat-stream` can have a stream piped in to them
and they will collect the data for you. Once the stream has ended, a
callback will be fired with the data:
response.pipe(bl(function (err, data) { ... }))
Note that you will probably need to `data.toString()` to convert from
a Buffer.
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httpCollect.js
const bl = require("bl"); var http = require('http'); http.get(process.argv[2], function(res) { res.pipe(bl(function(err,data){ console.log(data.length); console.log(data.toString()); })); });