جولة في Postman

Written Explanation

Getting started

You can use Postman as a desktop app or in the browser. Creating an account is optional for some uses and required for others, and the sign-in options change over time, so follow Postman's own start-up screens. This course does not need any paid feature. If you prefer not to sign in, look for a lightweight or scratch-pad mode in your version; if none is offered, signing in with an account you control is a normal step.

Whenever you start a task you will open a new request tab. Everything below happens in that tab.

The request builder

Postman's documentation describes the steps for a request in this order:

1. Set the method and URL. The method defaults to GET. Pick another from the drop-down (POST, PUT, PATCH, DELETE) and type the endpoint address next to it.
2. Add query parameters. Type them in the URL, or use the Params tab, which shows each one as a key and value row.
3. Add headers, body, and authorization. Headers go in the Headers tab; a body goes in the Body tab; credentials, if an API needs them, go in the Authorization tab.
4. Send. The Send button submits the request.
5. Read the response. The response pane shows the result.
6. Save the request, optionally into a collection.

Think of it as an order form with labeled boxes. Everything you learned in Module BEG-052 appears in a box.

Params tab and the URL

The URL bar and the Params tab are two views of the same thing. If you type https://dummyjson.com/products?limit=2 into the bar, the Params tab shows a row with key limit and value 2. If you add a row select with value title,price, the URL bar updates to ...?limit=2&select=title,price. Use whichever you find easier. The Params tab is handy when values are long or you want to switch parameters on and off with a checkbox.

Headers and body

For a GET you rarely need anything here. For a POST or PUT that sends JSON you need two things:

• In Headers, a Content-Type header with the value application/json. (Postman often adds this for you when you choose a JSON body type; open the headers list and check, since automatically added headers may be hidden by default.)
• In Body, choose the raw option and the JSON type, then type the JSON text.

The header tells the server how to read the body. A body without the right Content-Type is a classic reason for a 400 or 415 response.

The response pane

After Send, look for:

Postman also lets you search the body, or filter JSON with JSONPath, which is useful with large answers.

Collections

A collection is a saved group of requests that you can organize, find again, and share. Naming requests clearly ("List products", "One product", "Search") turns a collection into living documentation of an API. The collection format is a portable, open file format that people and tools can read.

To save: use the Save control on a request, give it a name, and choose or create a collection. To export a collection as a file, Postman's documentation says to open the collection's actions menu (the three-dot icon), choose the export option under More, and start the JSON download from the dialog. A teammate can then import that file into their own Postman. Menu names move between versions, so look under the collection's actions menu.

Variables

Typing https://dummyjson.com into twenty requests is tiring, and changing it later is worse. A variable stores a value once. You reference it with double curly braces. If a variable baseUrl holds https://dummyjson.com, then the URL {{baseUrl}}/products is sent to https://dummyjson.com/products.

Postman has different scopes of variables. A collection variable is available to every request in that collection. An environment variable belongs to an environment (for example "local", "test", "production"), and only one environment is active at a time. For this module, a collection variable named baseUrl is enough. Later, when your own API runs on localhost during development and on a server in production, environments let you switch the host with one click.