feat: add 'back/front end' in curriculum (#42596)
* chore: rename APIs and Microservices to include "Backend" (#42515) * fix typo * fix typo * undo change * Corrected grammar mistake Corrected a grammar mistake by removing a comma. * change APIs and Microservices cert title * update title * Change APIs and Microservices certi title * Update translations.json * update title * feat(curriculum): rename apis and microservices cert * rename folder structure * rename certificate * rename learn Markdown * apis-and-microservices -> back-end-development-and-apis * update backend meta * update i18n langs and cypress test Co-authored-by: Shaun Hamilton <shauhami020@gmail.com> * fix: add development to front-end libraries (#42512) * fix: added-the-word-Development-to-front-end-libraries * fix/added-the-word-Development-to-front-end-libraries * fix/added-word-development-to-front-end-libraries-in-other-related-files * fix/added-the-word-Development-to-front-end-and-all-related-files * fix/removed-typos-from-last-commit-in-index.md * fix/reverted-changes-that-i-made-to-dependecies * fix/removed xvfg * fix/reverted changes that i made to package.json * remove unwanted changes * front-end-development-libraries changes * rename backend certSlug and README * update i18n folder names and keys * test: add legacy path redirect tests This uses serve.json from the client-config repo, since we currently use that in production * fix: create public dir before moving serve.json * fix: add missing script * refactor: collect redirect tests * test: convert to cy.location for stricter tests * rename certificate folder to 00-certificates * change crowdin config to recognise new certificates location * allow translations to be used Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com> * add forwards slashes to path redirects * fix cypress path tests again * plese cypress * fix: test different challenge Okay so I literally have no idea why this one particular challenge fails in Cypress Firefox ONLY. Tom and I paired and spun a full build instance and confirmed in Firefox the page loads and redirects as expected. Changing to another bootstrap challenge passes Cypress firefox locally. Absolutely boggled by this. AAAAAAAAAAAAAAA * fix: separate the test Okay apparently the test does not work unless we separate it into a different `it` statement. >:( >:( >:( >:( Co-authored-by: Sujal Gupta <55016909+heysujal@users.noreply.github.com> Co-authored-by: Noor Fakhry <65724923+NoorFakhry@users.noreply.github.com> Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com> Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com>
This commit is contained in:
Shaun Hamilton
GitHub
@ -0,0 +1,79 @@
|
||||
---
|
||||
id: 587d7fb1367417b2b2512bf4
|
||||
title: Chain Middleware to Create a Time Server
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challengeType: 2
|
||||
forumTopicId: 301510
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dashedName: chain-middleware-to-create-a-time-server
|
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---
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|
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# --description--
|
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Middleware can be mounted at a specific route using `app.METHOD(path, middlewareFunction)`. Middleware can also be chained inside route definition.
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Look at the following example:
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|
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```js
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app.get('/user', function(req, res, next) {
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req.user = getTheUserSync(); // Hypothetical synchronous operation
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next();
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}, function(req, res) {
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res.send(req.user);
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});
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```
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This approach is useful to split the server operations into smaller units. That leads to a better app structure, and the possibility to reuse code in different places. This approach can also be used to perform some validation on the data. At each point of the middleware stack you can block the execution of the current chain and pass control to functions specifically designed to handle errors. Or you can pass control to the next matching route, to handle special cases. We will see how in the advanced Express section.
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# --instructions--
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In the route `app.get('/now', ...)` chain a middleware function and the final handler. In the middleware function you should add the current time to the request object in the `req.time` key. You can use `new Date().toString()`. In the handler, respond with a JSON object, taking the structure `{time: req.time}`.
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**Note:** The test will not pass if you don’t chain the middleware. If you mount the function somewhere else, the test will fail, even if the output result is correct.
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# --hints--
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The /now endpoint should have mounted middleware
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/chain-middleware-time').then(
|
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(data) => {
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assert.equal(
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data.stackLength,
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2,
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'"/now" route has no mounted middleware'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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The /now endpoint should return a time that is +/- 20 secs from now
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/chain-middleware-time').then(
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(data) => {
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var now = new Date();
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assert.isAtMost(
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Math.abs(new Date(data.time) - now),
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20000,
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'the returned time is not between +- 20 secs from now'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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# --solutions--
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|
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```js
|
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/**
|
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Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
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Please check our contributing guidelines to learn more.
|
||||
*/
|
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```
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@ -0,0 +1,78 @@
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---
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id: 587d7fb2367417b2b2512bf8
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title: Get Data from POST Requests
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challengeType: 2
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forumTopicId: 301511
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dashedName: get-data-from-post-requests
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---
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# --description--
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Mount a POST handler at the path `/name`. It’s the same path as before. We have prepared a form in the html frontpage. It will submit the same data of exercise 10 (Query string). If the body-parser is configured correctly, you should find the parameters in the object `req.body`. Have a look at the usual library example:
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<blockquote>route: POST '/library'<br>urlencoded_body: userId=546&bookId=6754 <br>req.body: {userId: '546', bookId: '6754'}</blockquote>
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Respond with the same JSON object as before: `{name: 'firstname lastname'}`. Test if your endpoint works using the html form we provided in the app frontpage.
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Tip: There are several other http methods other than GET and POST. And by convention there is a correspondence between the http verb, and the operation you are going to execute on the server. The conventional mapping is:
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POST (sometimes PUT) - Create a new resource using the information sent with the request,
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GET - Read an existing resource without modifying it,
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PUT or PATCH (sometimes POST) - Update a resource using the data sent,
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DELETE => Delete a resource.
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There are also a couple of other methods which are used to negotiate a connection with the server. Except from GET, all the other methods listed above can have a payload (i.e. the data into the request body). The body-parser middleware works with these methods as well.
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# --hints--
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|
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Test 1 : Your API endpoint should respond with the correct name
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```js
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(getUserInput) =>
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$.post(getUserInput('url') + '/name', { first: 'Mick', last: 'Jagger' }).then(
|
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(data) => {
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assert.equal(
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data.name,
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'Mick Jagger',
|
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'Test 1: "POST /name" route does not behave as expected'
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);
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},
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(xhr) => {
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throw new Error(xhr.responseText);
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}
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);
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```
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|
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Test 2 : Your API endpoint should respond with the correct name
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|
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```js
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(getUserInput) =>
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$.post(getUserInput('url') + '/name', {
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first: 'Keith',
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last: 'Richards'
|
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}).then(
|
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(data) => {
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assert.equal(
|
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data.name,
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'Keith Richards',
|
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'Test 2: "POST /name" route does not behave as expected'
|
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);
|
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},
|
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(xhr) => {
|
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throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
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@ -0,0 +1,67 @@
|
||||
---
|
||||
id: 587d7fb2367417b2b2512bf6
|
||||
title: Get Query Parameter Input from the Client
|
||||
challengeType: 2
|
||||
forumTopicId: 301512
|
||||
dashedName: get-query-parameter-input-from-the-client
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
Another common way to get input from the client is by encoding the data after the route path, using a query string. The query string is delimited by a question mark (?), and includes field=value couples. Each couple is separated by an ampersand (&). Express can parse the data from the query string, and populate the object `req.query`. Some characters, like the percent (%), cannot be in URLs and have to be encoded in a different format before you can send them. If you use the API from JavaScript, you can use specific methods to encode/decode these characters.
|
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|
||||
<blockquote>route_path: '/library'<br>actual_request_URL: '/library?userId=546&bookId=6754' <br>req.query: {userId: '546', bookId: '6754'}</blockquote>
|
||||
|
||||
# --instructions--
|
||||
|
||||
Build an API endpoint, mounted at `GET /name`. Respond with a JSON document, taking the structure `{ name: 'firstname lastname'}`. The first and last name parameters should be encoded in a query string e.g. `?first=firstname&last=lastname`.
|
||||
|
||||
**Note:** In the following exercise you are going to receive data from a POST request, at the same `/name` route path. If you want, you can use the method `app.route(path).get(handler).post(handler)`. This syntax allows you to chain different verb handlers on the same path route. You can save a bit of typing, and have cleaner code.
|
||||
|
||||
# --hints--
|
||||
|
||||
Test 1 : Your API endpoint should respond with the correct name
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/name?first=Mick&last=Jagger').then(
|
||||
(data) => {
|
||||
assert.equal(
|
||||
data.name,
|
||||
'Mick Jagger',
|
||||
'Test 1: "GET /name" route does not behave as expected'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
Test 2 : Your API endpoint should respond with the correct name
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/name?last=Richards&first=Keith').then(
|
||||
(data) => {
|
||||
assert.equal(
|
||||
data.name,
|
||||
'Keith Richards',
|
||||
'Test 2: "GET /name" route does not behave as expected'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,65 @@
|
||||
---
|
||||
id: 587d7fb2367417b2b2512bf5
|
||||
title: Get Route Parameter Input from the Client
|
||||
challengeType: 2
|
||||
forumTopicId: 301513
|
||||
dashedName: get-route-parameter-input-from-the-client
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
When building an API, we have to allow users to communicate to us what they want to get from our service. For example, if the client is requesting information about a user stored in the database, they need a way to let us know which user they're interested in. One possible way to achieve this result is by using route parameters. Route parameters are named segments of the URL, delimited by slashes (/). Each segment captures the value of the part of the URL which matches its position. The captured values can be found in the `req.params` object.
|
||||
|
||||
<blockquote>route_path: '/user/:userId/book/:bookId'<br>actual_request_URL: '/user/546/book/6754' <br>req.params: {userId: '546', bookId: '6754'}</blockquote>
|
||||
|
||||
# --instructions--
|
||||
|
||||
Build an echo server, mounted at the route `GET /:word/echo`. Respond with a JSON object, taking the structure `{echo: word}`. You can find the word to be repeated at `req.params.word`. You can test your route from your browser's address bar, visiting some matching routes, e.g. `your-app-rootpath/freecodecamp/echo`.
|
||||
|
||||
# --hints--
|
||||
|
||||
Test 1 : Your echo server should repeat words correctly
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/eChOtEsT/echo').then(
|
||||
(data) => {
|
||||
assert.equal(
|
||||
data.echo,
|
||||
'eChOtEsT',
|
||||
'Test 1: the echo server is not working as expected'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
Test 2 : Your echo server should repeat words correctly
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/ech0-t3st/echo').then(
|
||||
(data) => {
|
||||
assert.equal(
|
||||
data.echo,
|
||||
'ech0-t3st',
|
||||
'Test 2: the echo server is not working as expected'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,57 @@
|
||||
---
|
||||
id: 587d7fb1367417b2b2512bf3
|
||||
title: Implement a Root-Level Request Logger Middleware
|
||||
challengeType: 2
|
||||
forumTopicId: 301514
|
||||
dashedName: implement-a-root-level-request-logger-middleware
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
Earlier, you were introduced to the `express.static()` middleware function. Now it’s time to see what middleware is, in more detail. Middleware functions are functions that take 3 arguments: the request object, the response object, and the next function in the application’s request-response cycle. These functions execute some code that can have side effects on the app, and usually add information to the request or response objects. They can also end the cycle by sending a response when some condition is met. If they don’t send the response when they are done, they start the execution of the next function in the stack. This triggers calling the 3rd argument, `next()`.
|
||||
|
||||
Look at the following example:
|
||||
|
||||
```js
|
||||
function(req, res, next) {
|
||||
console.log("I'm a middleware...");
|
||||
next();
|
||||
}
|
||||
```
|
||||
|
||||
Let’s suppose you mounted this function on a route. When a request matches the route, it displays the string “I’m a middleware…”, then it executes the next function in the stack. In this exercise, you are going to build root-level middleware. As you have seen in challenge 4, to mount a middleware function at root level, you can use the `app.use(<mware-function>)` method. In this case, the function will be executed for all the requests, but you can also set more specific conditions. For example, if you want a function to be executed only for POST requests, you could use `app.post(<mware-function>)`. Analogous methods exist for all the HTTP verbs (GET, DELETE, PUT, …).
|
||||
|
||||
# --instructions--
|
||||
|
||||
Build a simple logger. For every request, it should log to the console a string taking the following format: `method path - ip`. An example would look like this: `GET /json - ::ffff:127.0.0.1`. Note that there is a space between `method` and `path` and that the dash separating `path` and `ip` is surrounded by a space on both sides. You can get the request method (http verb), the relative route path, and the caller’s ip from the request object using `req.method`, `req.path` and `req.ip`. Remember to call `next()` when you are done, or your server will be stuck forever. Be sure to have the ‘Logs’ opened, and see what happens when some request arrives.
|
||||
|
||||
**Note:** Express evaluates functions in the order they appear in the code. This is true for middleware too. If you want it to work for all the routes, it should be mounted before them.
|
||||
|
||||
# --hints--
|
||||
|
||||
Root level logger middleware should be active
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/_api/root-middleware-logger').then(
|
||||
(data) => {
|
||||
assert.isTrue(
|
||||
data.passed,
|
||||
'root-level logger is not working as expected'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,53 @@
|
||||
---
|
||||
id: 587d7fb0367417b2b2512bed
|
||||
title: Meet the Node console
|
||||
challengeType: 2
|
||||
forumTopicId: 301515
|
||||
dashedName: meet-the-node-console
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
Working on these challenges will involve you writing your code using one of the following methods:
|
||||
|
||||
- Clone [this GitHub repo](https://github.com/freeCodeCamp/boilerplate-express/) and complete these challenges locally.
|
||||
- Use [our Replit starter project](https://replit.com/github/freeCodeCamp/boilerplate-express) to complete these challenges.
|
||||
- Use a site builder of your choice to complete the project. Be sure to incorporate all the files from our GitHub repo.
|
||||
|
||||
When you are done, make sure a working demo of your project is hosted somewhere public. Then submit the URL to it in the `Solution Link` field.
|
||||
|
||||
During the development process, it is important to be able to check what’s going on in your code.
|
||||
|
||||
Node is just a JavaScript environment. Like client side JavaScript, you can use the console to display useful debug information. On your local machine, you would see console output in a terminal. On Replit, a terminal is open in the right pane by default.
|
||||
|
||||
We recommend to keep the terminal open while working at these challenges. By reading the output in the terminal, you can see any errors that may occur.
|
||||
|
||||
# --instructions--
|
||||
|
||||
Modify the `myApp.js` file to log "Hello World" to the console.
|
||||
|
||||
# --hints--
|
||||
|
||||
`"Hello World"` should be in the console
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/_api/hello-console').then(
|
||||
(data) => {
|
||||
assert.isTrue(data.passed, '"Hello World" is not in the server console');
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,51 @@
|
||||
---
|
||||
id: 587d7fb0367417b2b2512bef
|
||||
title: Serve an HTML File
|
||||
challengeType: 2
|
||||
forumTopicId: 301516
|
||||
dashedName: serve-an-html-file
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
You can respond to requests with a file using the `res.sendFile(path)` method. You can put it inside the `app.get('/', ...)` route handler. Behind the scenes, this method will set the appropriate headers to instruct your browser on how to handle the file you want to send, according to its type. Then it will read and send the file. This method needs an absolute file path. We recommend you to use the Node global variable `__dirname` to calculate the path like this:
|
||||
|
||||
```js
|
||||
absolutePath = __dirname + relativePath/file.ext
|
||||
```
|
||||
|
||||
# --instructions--
|
||||
|
||||
Send the `/views/index.html` file as a response to GET requests to the `/` path. If you view your live app, you should see a big HTML heading (and a form that we will use later…), with no style applied.
|
||||
|
||||
**Note:** You can edit the solution of the previous challenge or create a new one. If you create a new solution, keep in mind that Express evaluates routes from top to bottom, and executes the handler for the first match. You have to comment out the preceding solution, or the server will keep responding with a string.
|
||||
|
||||
# --hints--
|
||||
|
||||
Your app should serve the file views/index.html
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url')).then(
|
||||
(data) => {
|
||||
assert.match(
|
||||
data,
|
||||
/<h1>.*<\/h1>/,
|
||||
'Your app does not serve the expected HTML'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,47 @@
|
||||
---
|
||||
id: 587d7fb1367417b2b2512bf1
|
||||
title: Serve JSON on a Specific Route
|
||||
challengeType: 2
|
||||
forumTopicId: 301517
|
||||
dashedName: serve-json-on-a-specific-route
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
While an HTML server serves HTML, an API serves data. A <dfn>REST</dfn> (REpresentational State Transfer) API allows data exchange in a simple way, without the need for clients to know any detail about the server. The client only needs to know where the resource is (the URL), and the action it wants to perform on it (the verb). The GET verb is used when you are fetching some information, without modifying anything. These days, the preferred data format for moving information around the web is JSON. Simply put, JSON is a convenient way to represent a JavaScript object as a string, so it can be easily transmitted.
|
||||
|
||||
Let's create a simple API by creating a route that responds with JSON at the path `/json`. You can do it as usual, with the `app.get()` method. Inside the route handler, use the method `res.json()`, passing in an object as an argument. This method closes the request-response loop, returning the data. Behind the scenes, it converts a valid JavaScript object into a string, then sets the appropriate headers to tell your browser that you are serving JSON, and sends the data back. A valid object has the usual structure `{key: data}`. `data` can be a number, a string, a nested object or an array. `data` can also be a variable or the result of a function call, in which case it will be evaluated before being converted into a string.
|
||||
|
||||
# --instructions--
|
||||
|
||||
Serve the object `{"message": "Hello json"}` as a response, in JSON format, to GET requests to the `/json` route. Then point your browser to `your-app-url/json`, you should see the message on the screen.
|
||||
|
||||
# --hints--
|
||||
|
||||
The endpoint `/json` should serve the json object `{"message": "Hello json"}`
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/json').then(
|
||||
(data) => {
|
||||
assert.equal(
|
||||
data.message,
|
||||
'Hello json',
|
||||
"The '/json' endpoint does not serve the right data"
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,51 @@
|
||||
---
|
||||
id: 587d7fb0367417b2b2512bf0
|
||||
title: Serve Static Assets
|
||||
challengeType: 2
|
||||
forumTopicId: 301518
|
||||
dashedName: serve-static-assets
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
An HTML server usually has one or more directories that are accessible by the user. You can place there the static assets needed by your application (stylesheets, scripts, images).
|
||||
|
||||
In Express, you can put in place this functionality using the middleware `express.static(path)`, where the `path` parameter is the absolute path of the folder containing the assets.
|
||||
|
||||
If you don’t know what middleware is... don’t worry, we will discuss in detail later. Basically, middleware are functions that intercept route handlers, adding some kind of information. A middleware needs to be mounted using the method `app.use(path, middlewareFunction)`. The first `path` argument is optional. If you don’t pass it, the middleware will be executed for all requests.
|
||||
|
||||
# --instructions--
|
||||
|
||||
Mount the `express.static()` middleware to the path `/public` with `app.use()`. The absolute path to the assets folder is `__dirname + /public`.
|
||||
|
||||
Now your app should be able to serve a CSS stylesheet. Note that the `/public/style.css` file is referenced in the `/views/index.html` in the project boilerplate. Your front-page should look a little better now!
|
||||
|
||||
# --hints--
|
||||
|
||||
Your app should serve asset files from the `/public` directory to the `/public` path
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/public/style.css').then(
|
||||
(data) => {
|
||||
assert.match(
|
||||
data,
|
||||
/body\s*\{[^\}]*\}/,
|
||||
'Your app does not serve static assets'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,57 @@
|
||||
---
|
||||
id: 587d7fb0367417b2b2512bee
|
||||
title: Start a Working Express Server
|
||||
challengeType: 2
|
||||
forumTopicId: 301519
|
||||
dashedName: start-a-working-express-server
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
In the first two lines of the file `myApp.js`, you can see how easy it is to create an Express app object. This object has several methods, and you will learn many of them in these challenges. One fundamental method is `app.listen(port)`. It tells your server to listen on a given port, putting it in running state. For testing reasons, we need the app to be running in the background so we added this method in the `server.js` file for you.
|
||||
|
||||
Let’s serve our first string! In Express, routes takes the following structure: `app.METHOD(PATH, HANDLER)`. METHOD is an http method in lowercase. PATH is a relative path on the server (it can be a string, or even a regular expression). HANDLER is a function that Express calls when the route is matched. Handlers take the form `function(req, res) {...}`, where req is the request object, and res is the response object. For example, the handler
|
||||
|
||||
```js
|
||||
function(req, res) {
|
||||
res.send('Response String');
|
||||
}
|
||||
```
|
||||
|
||||
will serve the string 'Response String'.
|
||||
|
||||
# --instructions--
|
||||
|
||||
Use the `app.get()` method to serve the string "Hello Express" to GET requests matching the `/` (root) path. Be sure that your code works by looking at the logs, then see the results in the preview if you are using Replit.
|
||||
|
||||
**Note:** All the code for these lessons should be added in between the few lines of code we have started you off with.
|
||||
|
||||
# --hints--
|
||||
|
||||
Your app should serve the string 'Hello Express'
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url')).then(
|
||||
(data) => {
|
||||
assert.equal(
|
||||
data,
|
||||
'Hello Express',
|
||||
'Your app does not serve the text "Hello Express"'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,63 @@
|
||||
---
|
||||
id: 587d7fb2367417b2b2512bf7
|
||||
title: Use body-parser to Parse POST Requests
|
||||
challengeType: 2
|
||||
forumTopicId: 301520
|
||||
dashedName: use-body-parser-to-parse-post-requests
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
Besides GET, there is another common HTTP verb, it is POST. POST is the default method used to send client data with HTML forms. In REST convention, POST is used to send data to create new items in the database (a new user, or a new blog post). You don’t have a database in this project, but you are going to learn how to handle POST requests anyway.
|
||||
|
||||
In these kind of requests, the data doesn’t appear in the URL, it is hidden in the request body. The body is a part of the HTTP request, also called the payload. Even though the data is not visible in the URL, this does not mean that it is private. To see why, look at the raw content of an HTTP POST request:
|
||||
|
||||
```http
|
||||
POST /path/subpath HTTP/1.0
|
||||
From: john@example.com
|
||||
User-Agent: someBrowser/1.0
|
||||
Content-Type: application/x-www-form-urlencoded
|
||||
Content-Length: 20
|
||||
|
||||
name=John+Doe&age=25
|
||||
```
|
||||
|
||||
As you can see, the body is encoded like the query string. This is the default format used by HTML forms. With Ajax, you can also use JSON to handle data having a more complex structure. There is also another type of encoding: multipart/form-data. This one is used to upload binary files. In this exercise, you will use a urlencoded body. To parse the data coming from POST requests, you have to install the `body-parser` package. This package allows you to use a series of middleware, which can decode data in different formats.
|
||||
|
||||
# --instructions--
|
||||
|
||||
Install the `body-parser` module in your `package.json`. Then, `require` it at the top of the file. Store it in a variable named `bodyParser`. The middleware to handle urlencoded data is returned by `bodyParser.urlencoded({extended: false})`. Pass the function returned by the previous method call to `app.use()`. As usual, the middleware must be mounted before all the routes that depend on it.
|
||||
|
||||
**Note:** `extended` is a configuration option that tells `body-parser` which parsing needs to be used. When `extended=false` it uses the classic encoding `querystring` library. When `extended=true` it uses `qs` library for parsing.
|
||||
|
||||
When using `extended=false`, values can be only strings or arrays. The object returned when using `querystring` does not prototypically inherit from the default JavaScript `Object`, which means functions like `hasOwnProperty`, `toString` will not be available. The extended version allows more data flexibility, but it is outmatched by JSON.
|
||||
|
||||
# --hints--
|
||||
|
||||
The 'body-parser' middleware should be mounted
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/_api/add-body-parser').then(
|
||||
(data) => {
|
||||
assert.isAbove(
|
||||
data.mountedAt,
|
||||
0,
|
||||
'"body-parser" is not mounted correctly'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
@ -0,0 +1,52 @@
|
||||
---
|
||||
id: 587d7fb1367417b2b2512bf2
|
||||
title: Use the .env File
|
||||
challengeType: 2
|
||||
forumTopicId: 301521
|
||||
dashedName: use-the--env-file
|
||||
---
|
||||
|
||||
# --description--
|
||||
|
||||
The `.env` file is a hidden file that is used to pass environment variables to your application. This file is secret, no one but you can access it, and it can be used to store data that you want to keep private or hidden. For example, you can store API keys from external services or your database URI. You can also use it to store configuration options. By setting configuration options, you can change the behavior of your application, without the need to rewrite some code.
|
||||
|
||||
The environment variables are accessible from the app as `process.env.VAR_NAME`. The `process.env` object is a global Node object, and variables are passed as strings. By convention, the variable names are all uppercase, with words separated by an underscore. The `.env` is a shell file, so you don’t need to wrap names or values in quotes. It is also important to note that there cannot be space around the equals sign when you are assigning values to your variables, e.g. `VAR_NAME=value`. Usually, you will put each variable definition on a separate line.
|
||||
|
||||
# --instructions--
|
||||
|
||||
Let's add an environment variable as a configuration option.
|
||||
|
||||
Create a `.env` file in the root of your project directory, and store the variable `MESSAGE_STYLE=uppercase` in it.
|
||||
|
||||
Then, in the `/json` GET route handler you created in the last challenge, transform the response object's message to uppercase if `process.env.MESSAGE_STYLE` equals `uppercase`. The response object should either be `{"message": "Hello json"}` or `{"message": "HELLO JSON"}`, depending on the `MESSAGE_STYLE` value.
|
||||
|
||||
**Note:** If you are using Replit, you cannot create a `.env` file. Instead, use the built-in <dfn>SECRETS</dfn> tab to add the variable.
|
||||
|
||||
# --hints--
|
||||
|
||||
The response of the endpoint `/json` should change according to the environment variable `MESSAGE_STYLE`
|
||||
|
||||
```js
|
||||
(getUserInput) =>
|
||||
$.get(getUserInput('url') + '/_api/use-env-vars').then(
|
||||
(data) => {
|
||||
assert.isTrue(
|
||||
data.passed,
|
||||
'The response of "/json" does not change according to MESSAGE_STYLE'
|
||||
);
|
||||
},
|
||||
(xhr) => {
|
||||
throw new Error(xhr.responseText);
|
||||
}
|
||||
);
|
||||
```
|
||||
|
||||
# --solutions--
|
||||
|
||||
```js
|
||||
/**
|
||||
Backend challenges don't need solutions,
|
||||
because they would need to be tested against a full working project.
|
||||
Please check our contributing guidelines to learn more.
|
||||
*/
|
||||
```
|
||||
Reference in New Issue
Block a user