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To parse incoming data, again we need some data and I'll get it from the pure Node.js file,

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I will simply copy this response here with the back ticks and replace my response here,

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this string with that copied string, so that again I try to output a user name and I have a form here.

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Now the user name is not always set,

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so here I want to have a default user name and then also get a body though which allows me to get the

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user name from that, like this.

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However actually we can remove the if block because we'll get the user name out of the request body

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a bit differently. Instead of manually parsing the body like that, with Express.js we can use a middleware

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that does this body parsing for us.

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So before we do anything with the response, we could have another middleware where in the function we

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execute there, we have all the body parsing logic so that in the subsequent middlewares, we get the parsed

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body available. We could write our own function for that but thankfully, there are third-party packages

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which can be integrated into this Express middleware flow that do that for us and the very popular package

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for parsing the request body and adding it to the request object,

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so adding the parsed body to the request object is the body-parser package.

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You can install this with npm install body-parser --save to add an entry to package.json

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and by hitting enter

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this will now be installed and is made available in your project.

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Now we just have to import it here,

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body parser by requiring body-parser and now body parser and that's the convenient thing can

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simply be added here as a middleware,

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we just have to pick one of the parsing methods,

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for example JSON if we had JSON data or in our case here, URL encoded which is essentially the

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form data we will receive and if we do that, this package will add a default middleware,

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so it adds a function like this basically to the Express middleware flow where it parses and extracts

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the incoming body, the request body and adds the parsed body back into that body field on the request object,

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so that now here we could say we want to set the user name, which now can be a constant, equal to

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request.body.username because we gave our input here a name of user name,

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so this will be the key by which we can access the field value or unknown user, if that should be undefined

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for whatever reason.

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And now with that let's give it a try, let's restart our server by again running app.js again and what

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one thinks we should apply here because we get the warning here, we should add an options object to URL

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encoded and said extended to false there which just controls how the body is parsed and this

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default setting should be fine

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so now we can start this without getting a warning

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and now if we go into the URL again and hit enter here, don't reload but hit enter in the URL, you

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see hi unknown user and

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now if you enter for example Anna here, you see Anna here as an output and we do see that here because of

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that body parser package which does that.

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So this is how we can parse the body with the help of this package and with the help of Express which

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makes it possible to use this package and that's of course more convenient than manually parsing the

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body like that. With that we got a basic setup with Express.js but now it would also be nice to

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not just send back HTML code like this in line, in our Javascript file but maybe send back a separate

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HTML file or even a dynamic template file which renders HTML but which also gives us dynamic

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injection points, where we can inject dynamic content because that's what we typically want to do. We

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want to prepare some content on the server and then create an HTML file which has some static elements

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that always are the same and some dynamic parts which depend on the data we generated on the server

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and that's what we'll do next.