December 15, 2018


Exception Handling

JAX-RS 2.0 has added a nice exception hierarchy for various HTTP error conditions. So, instead of creating an instance of WebApplicationException and initializing it with a specific status code, you can use one of these exceptions instead.

Exception Status Code Description
BadRequestException 400 Malformed message
NotAuthorizedException 401 Authentication failure
ForbiddenException 403 Not permitted to access
NotFoundException 404 Couldn’t find resource
NotAllowedException 405 HTTP method not supported
NotAcceptableException 406 Client media type requested not supported
NotSupportedException 415 Client posted media type not supported
InternalServerErrorException 500 General server error
ServiceUnavailableException 503 Server is temporarily unavailable or busy

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

-d, --data <data> Send specified data in POST request. Details provided below.

-f, --fail Fail silently (don’t output HTML error form if returned).

-F, --form <name=content> Submit form data.

-H, --header <header> Headers to supply with request.

-i, --include Include HTTP headers in the output.

-I, --head Fetch headers only.

-k, --insecure Allow insecure connections to succeed.

-L, --location Follow redirects.

-o, --output <file> Write output to . Can use --create-dirs in conjunction with this to create any directories specified in the -o path.

-O, --remote-name Write output to file named like the remote file (only writes to current directory).

-s, --silent Silent (quiet) mode. Use with -S to force it to show errors.

-v, --verbose Provide more information (useful for debugging).

-w, --write-out <format> Make curl display information on stdout after a completed transfer. See man page for more details on available variables. Convenient way to force curl to append a newline to output: -w "\n" (can add to ~/.curlrc).

-X, --request The request method to use.


When sending data via a POST or PUT request, two common formats (specified via the Content-Type header) are:

  • application/json
  • application/x-www-form-urlencoded

Many APIs will accept both formats, so if you’re using curl at the command line, it can be a bit easier to use the form urlencoded format instead of json because

  • the json format requires a bunch of extra quoting
  • curl will send form urlencoded by default, so for json the Content-Type header must be explicitly set

This gist provides examples for using both formats, including how to use sample data files in either format with your curl requests.

curl usage

For sending data with POST and PUT requests, these are common curl options:

  • request type

    • -X POST
    • -X PUT
  • content type header

  • -H "Content-Type: application/x-www-form-urlencoded"

  • -H "Content-Type: application/json"

  • data

    • form urlencoded: -d "param1=value1&param2=value2" or -d @data.txt
    • json: -d '{"key1":"value1", "key2":"value2"}' or -d @data.json


POST application/x-www-form-urlencoded

application/x-www-form-urlencoded is the default:

curl -d "param1=value1&param2=value2" -X POST http://localhost:3000/data


curl -d "param1=value1&param2=value2" -H "Content-Type: application/x-www-form-urlencoded" -X POST http://localhost:3000/data

with a data file

curl -d "@data.txt" -X POST http://localhost:3000/data

POST application/json

curl -d '{"key1":"value1", "key2":"value2"}' -H "Content-Type: application/json" -X POST http://localhost:3000/data

with a data file

curl -d "@data.json" -X POST http://localhost:3000/data

POSTing Files with cURL

curl -X POST -F 'image=@/path/to/pictures/picture.jpg' http://domain.tld/upload

POSTing Form Data with cURL

Start your cURL command with curl -X POST and then add -F for every field=value you want to add to the POST:

curl -X POST -F 'username=davidwalsh' -F 'password=something' http://domain.tld/post-to-me.php

If you need to send a specific data type or header with cURL, use -H to add a header, -d to send raw data:

curl -X POST -H 'Content-Type: application/json' -d '{"username":"davidwalsh","password":"something"}' http://domain.tld/login