How Do I Obtain a User Token Using Postman?

Prerequisites

You have installed and registered with Postman.

NOTE:

• You are advised to install a Postman version that supports a header larger than 32 KB. Otherwise, a header overflow error may be reported.

Procedure

1. Edit the request URL, header, and body of the API used to obtain a token for calling APIs.
   • Request URL
     The request URL is in the format "https://IAM region and endpoint/API URI".

     1. Obtain the IAM region and endpoint.

          

     2. Obtain the API URI from Obtaining a User Token.

        For example, the request URL in the eu-west-101 region is https://iam.myhuaweicloud.eu/v3/auth/tokens.

     3. Select an API request method and enter the request URL in Postman.

          

   • Request Header

     Set key to Content-Type and value to application/json;charset=utf8.

       

   • Request Body
     Modify parameters in the example request body.

     {
     	"auth": {
     		"identity": {
     			"methods": [
                                     "password"
                              ],
     			"password": {
     				"user": {
     					"domain": {
     						"name": "Account name"
     					},
     					"name": "IAM user name",
     					"password": "IAM user password"
     				}
     			}
     		},
     		"scope": {
     			"domain": {
     				"name": "Account name"
     			}
     		}
     	}
       }

     NOTE:

     For details about how to obtain the account name and IAM user name, see Obtaining Account, IAM User, and Project Information.

2. Click Send to send the API request.

     

3. View the token in the response header. You can use this token for authentication when you call other IAM APIs.
   NOTE:

   • If error 401 is returned, the authentication has failed. Make sure that parameters in the request body are correct and send the request again.
   • If error 400 is returned, the body format is incorrect. Check whether the body format complies with the JSON syntax. For details, see Status Codes.
   • If "Header Overflow" is displayed, resolve the problem by referring to Why Am I Seeing a Message Indicating Header Overflow When I Attempt to Use Postman to Obtain a Token?

Why Am I Seeing a Message Indicating Header Overflow When I Attempt to Use Postman to Obtain a Token?

Postman of V7.25.0, V7.26.0, or a later version cannot be used to obtain a user token due to configurations. The message "Header Overflow" will be displayed if you use any of these versions.

• Solution 1

  Use an earlier version of Postman, such as V 5.xx.

• Solution 2:

  Use curl to obtain a token and replace the text in bold with actual values:

  curl -ik -X POST -H 'Content-Type=application/json;charset=utf8' -d '{"auth": {"identity": {"methods": ["password"],"password": {"user": {"domain": {"name": "Account name"},"name": "IAM username","password": "IAM user password"}}},"scope": {"domain": {"name": "Account name"}}}}' https://iam.myhuaweicloud.eu/v3/auth/tokens
• Solution 3

  Pass an additional environment variable NODE_OPTIONS=--max-http-header-size=16384 (16 KB) to Postman to specify the maximum size of the HTTP header (in bytes).

  Run one of the following commands depending on your OS:

  • macOS

    NODE_OPTIONS=--max-http-header-size=16384 /Applications/Postman.app/Contents/MacOS/Postman 
  • Linux

    NODE_OPTIONS=--max-http-header-size=16384 /path/to/Postman/Postman 
  • Windows

    set NODE_OPTIONS=--max-http-header-size=16384 
    C:\users\<username>\AppData\local\Postman\Postman.exe