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Resty

Resty is a tiny script wrapper for curl. It provides a simple, concise shell interface for interacting with REST services. Since it is implemented as functions in your shell and not in its own separate command environment you have access to all the powerful shell tools, such as perl, awk, grep, sed, etc. You can use resty in pipelines to process data from REST services, and PUT or POST the data right back. You can even pipe the data in and then edit it interactively in your text editor prior to PUT or POST.

Cookies are supported automatically and stored in a file locally. Most of the arguments are remembered from one call to the next to save typing. It has pretty good defaults for most purposes. Additionally, resty allows you to easily provide your own options to be passed directly to curl, so even the most complex requests can be accomplished with the minimum amount of command line pain.

Here is a nice screencast showing resty in action (by Jan-Piet Mens).

Quick Start

You have curl, right? Okay.

  curl -L http://github.com/micha/resty/raw/master/resty > resty

Source the script before using it. (You can put this line in your ~/.bashrc file if you want, or just paste the contents of the resty script right in there. Either way works.)

  . resty

Set the REST host to which you will be making your requests (you can do this whenever you want to change hosts, anytime).

  resty http://127.0.0.1:8080/data

Make some HTTP requests.

  GET /blogs.json
  PUT /blogs/2.json '{"title" : "updated post", "body" : "This is the new."}'
  DELETE /blogs/2
  POST /blogs.json '{"title" : "new post", "body" : "This is the new new."}'

Usage

  source resty [-W] [remote]              # load functions into shell
  resty                                   # prints current request URI base
  resty <remote> [OPTIONS]                # sets the base request URI

  HEAD [path] [OPTIONS]                   # HEAD request
  OPTIONS [path] [OPTIONS]                # OPTIONS request
  GET [path] [OPTIONS]                    # GET request 
  DELETE [path] [OPTIONS]                 # DELETE request 
  PUT [path] [data] [OPTIONS]             # PUT request
  POST [path] [data] [OPTIONS]            # POST request
  TRACE [path] [OPTIONS]                  # TRACE request

  Options:

  -Q            Don't URL encode the path.
  -q <query>    Send query string with the path. A '?' is prepended to
                <query> and concatenated onto the <path>.
  -W            Don't write to history file (only when sourcing script).
  -V            Edit the input data interactively in 'vi'. (PUT and POST
                requests only, with data piped to stdin.)
  -Z            Raw output. This disables any processing of HTML in the
                response.
  <curl opt>    Any curl options will be passed down to curl.

Request URI Base

The request URI base is what the eventual URI to which the requests will be made is based on. Specifically, it is a URI that may contain the * character one or more times. The * will be replaced with the path parameter in the OPTIONS, HEAD, GET, POST, PUT, or DELETE request as described above.

For example:

  resty 'http://127.0.0.1:8080/data*.json'

and then

  GET /5

would result in a GET request to the URI http://127.0.0.1:8080/data/5.json.

If no * character is specified when setting the base URI, it's just added onto the end for you automatically.

HTTPS URIs

HTTPS URIs can be used, as well. For example:

  resty 'https://example.com/doit'

URI Base History

The URI base is saved to an rc file (~/.resty/host) each time it's set, and the last setting is saved in an environment variable ($_resty_host). The URI base is read from the rc file when resty starts up, but only if the $_resty_host environment variable is not set. In this way you can make requests to different hosts using resty from separate terminals, and have a different URI base for each terminal.

If you want to see what the current URI base is, just run resty with no arguments. The URI base will be printed to stdout.

The Optional Path Parameter

The HTTP verbs (OPTIONS, HEAD, GET, POST, PUT, and DELETE) first argument is always an optional URI path. This path must always start with a / character. If the path parameter is not provided on the command line, resty will just use the last path it was provided with. This "last path" is stored in an environment variable ($_resty_path), so each terminal basically has its own "last path".

URL Encoding Of Path Parameter

Resty will always [URL encode] (http://www.blooberry.com/indexdot/html/topics/urlencoding.htm) the path, except for slashes. (Slashes in path elements need to be manually encoded as %2F.) This means that the ?, =, and & characters will be encoded, as well as some other problematic characters. To disable this behavior use the -Q option.

Query Strings

There are two ways to add a query string to the path. The first, mentioned above, is to disable URL encoding with the -Q option, and include the query string with the path parameter, like this:

  GET '/blogs/47?param=foo&otherparam=bar' -Q

To specify a query string without disabling URL encoding on the path the -q option is used, like this:

  GET /blogs/47 -q 'param=foo&otherparam=bar'

POST/PUT Requests and Data

Normally you would probably want to provide the request body data right on the command line like this:

  PUT /blogs/5.json '{"title" : "hello", "body" : "this is it"}'

But sometimes you will want to send the request body from a file instead. To do that you pipe in the contents of the file:

  PUT /blogs/5.json < /tmp/t

Or you can pipe the data from another program, like this:

  myprog | PUT /blogs/5.json

Or, interestingly, as a filter pipeline with jsawk:

  GET /blogs/5.json | jsawk 'this.author="Bob Smith";this.tags.push("news")' | PUT

Notice how the path argument is omitted from the PUT command.

Edit PUT/POST Data In Vi

With the -V options you can pipe data into PUT or POST, edit it in vi, save the data (using :wq in vi, as normal) and the resulting data is then PUT or POSTed. This is similar to the way visudo works, for example.

  GET /blogs/2 | PUT -V

This fetches the data and lets you edit it, and then does a PUT on the resource. If you don't like vi you can specify your preferred editor by setting the EDITOR environment variable.

Errors and Output

For successful 2xx responses, the response body is printed on stdout. You can pipe the output to stuff, process it, and then pipe it back to resty, if you want.

For responses other than 2xx the response body is dumped to stderr.

In either case, if the content type of the response is text/html, then resty will try to process the response through either lynx, html2text, or, finally, cat, depending on which of those programs are available on your system.

Raw Output (-Z option)

If you don't want resty to process the output through lynx or html2text you can use the -Z option, and get the raw output.

Passing Command Line Options To Curl

Anything after the (optional) path and data arguments is passed on to curl.

For example:

  GET /blogs.json -H "Range: items=1-10"

The -H "Range: items=1-10" argument will be passed to curl for you. This makes it possible to do some more complex operations when necessary.

  POST -v -u user:test

In this example the path and data arguments were left off, but -v and -u user:test will be passed through to curl, as you would expect.

Here are some useful options to try:

  • -v verbose output, shows HTTP headers and status on stderr
  • -j junk session cookies (refresh cookie-based session)
  • -u <username:password> HTTP basic authentication
  • -H <header> add request header (this option can be added more than once)

Default Curl Options

Sometimes you want to send some options to curl for every request. It would be tedious to have to repeat these options constantly. To tell resty to always add certain curl options you can specify those options when you call resty to set the URI base. For example:

  resty example.com:8080 -H "Accept: application/json" -u user:pass

Every subsequent request will have the -H "Accept:..." and -u user:... options automatically added. Each time resty is called this option list is reset.

Per-Host/Per-Method Curl Configuration Files

Resty supports a per-host/per-method configuration file to help you with frequently used curl options. Each host (including the port) can have its own configuration file in the ~/.resty directory. The file format is

  GET [arg] [arg] ...
  PUT [arg] [arg] ...
  POST [arg] [arg] ...
  DELETE [arg] [arg] ...

Where the args are curl command line arguments. Each line can specify arguments for that HTTP verb only, and all lines are optional.

So, suppose you find yourself using the same curl options over and over. You can save them in a file and resty will pass them to curl for you. Say this is a frequent pattern for you:

  resty localhost:8080
  GET /Blah -H "Accept: application/json"
  GET /Other -H "Accept: application/json"
  ...
  POST /Something -H "Content-Type: text/plain" -u user:pass
  POST /SomethingElse -H "Content-Type: text/plain" -u user:pass
  ...

It's annoying to add the -H and -u options to curl all the time. So create a file ~/.resty/localhost:8080, like this:

~/.resty/localhost:8080

  GET -H "Accept: application/json"
  POST -H "Content-Type: text/plain" -u user:pass

Then any GET or POST requests to localhost:8080 will have the specified options prepended to the curl command line arguments, saving you from having to type them out each time, like this:

  GET /Blah
  GET /Other
  ...
  POST /Something
  POST /SomethingElse
  ...

Sweet! Much better.

Exit Status

Successful requests (HTTP respose with 2xx status) return zero. Otherwise, the first digit of the response status is returned (i.e., 1 for 1xx, 3 for 3xx, 4 for 4xx, etc.) This is because the exit status is an 8 bit integer---it can't be greater than 255. If you want the exact status code you can always just pass the -v option to curl.

Using Resty In Shell Scripts

Since resty creates the REST verb functions in the shell, when using it from a script you must source it before you use any of the functions. However, it's likely that you don't want it to be overwriting the resty host history file, and you will almost always want to set the URI base explicitly.

  #!/usr/bin/env bash

  # Load resty, don't write to the history file, and set the URI base
  . /path/to/resty -W 'https://myhost.com/data*.json'

  # GET the JSON list of users, set each of their 'disabled' properties
  # to 'false', and PUT the modified JSON back
  GET /users | jsawk 'this.disabled = false' | PUT

Here the -W option was used when loading the script to prevent writing to the history file and an initial URI base was set at the same time. Then a JSON file was fetched, edited using jsawk, and re-uploaded to the server.

Working With JSON or XML Data

JSON REST web services require some special tools to make them accessible and easily manipulated in the shell environment. The following are a few scripts that make dealing with JSON data easier.

  • Jsawk can be used to process and filter JSON data from and to resty, in a shell pipeline. This takes care of parsing the input JSON correctly, rather than using regexes and sed, awk, perl or the like, and prints the resulting output in correct JSON format, as well.

    GET /blogs.json |jsawk -n 'out(this.title)' # prints all the blog titles

  • The included pp script will pretty-print JSON for you. You just need to install the JSON perl module from CPAN or you can use pypp if you have python 2.6 installed.

    GET /blogs.json |pp # pretty-prints the JSON output from resty

  • Another way to format JSON output:

    $ echo '{"json":"obj"}' | python -mjson.tool
{
  "json": "obj"
}

  • The tidy tool can be used to format HTML/XML:

    $ ~$ echo "<test><deep>value</deep></test>" | tidy -xml -q -i
<test>
  <deep>value</deep>
</test>