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AWNCORP JONASS MPERRY MIKEGRB BERNHARD

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1 non-PAUSE user.

Brian Phillips

NAME

presto - Command-line interface for RESTful web services

VERSION

version 0.009

SYNOPSIS

Invoke from the shell:

        bash$ presto http://my-server.com

Very basic usage:

        http://my-server.com> GET /product/1.json
        {"id":1,"name":"My Product"}

        http://my-server.com> HEAD /product/1.json
        HTTP/1.1 200 OK
        Connection: close
        Date: Thu, 28 Jun 2012 21:05:33 GMT
        Content-Length: 0
        Content-Type: application/json
        Client-Date: Thu, 28 Jun 2012 21:05:44 GMT
        Client-Response-Num: 1

DESCRIPTION

App::Presto provides a command-line interface (CLI) for RESTful web services. When looking for a way to interact with RESTful services answers typically point to some horrible GUI or (on the complete opposite end of the spectrum) just using curl directly on the command-line. This tool attempts to find some sort of middle ground by providing a quasi-DSL for interacting with a RESTful service in an interactive way.

FEATURES

Basic HTTP methods

All HTTP methods are implemented as commands in presto. The URL that is given is appended to the endpoint specified when presto is invoked as shown in the SYNOPSIS above.

Request Building

If the endpoint contains a * character the URL fragment specified in the GET/POST/etc command is inserted at that point. This allows you to do things like auto-append a file extension to all URLs. For instance:

        bash$ presto http://my-server.com*.json
        http://my-server.com> GET /product/1

In this case, the full URL would be http://my-server.com/product/1.json. If no * is found in the URL, the URL fragment is simply appended at the end of the endpoint.

All arguments after the first will be treated as query parameters (for GET/HEAD/DELETE requests) or request content (for POST/PUT requests). For instance:

        http://my-server.com> GET /products limit=10 offset=20
  # request goes to http://my-sever.com/products?limit=10&offset=20

        http://my-server.com> POST /products '{"name":"A New Product"}'
  # request goes to http://my-sever.com/products with the body as specified

You can also specify additional headers you would like included in the request:

        # the ":" is optional
        http://my-server.com> header Accept: application/json

        # shortcut for "header Content-Type application/json"
        http://my-server.com> type application/json

        # shortcut for "header Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
        http://my-server.com> authorization Aladdin 'open sesame'

        # view all headers
        http://my-server.com> headers

        # view specific header
        http://my-server.com> header Authorization

        # clear all headers
        http://my-server.com> headers --clear

        # unset specific header
        http://my-server.com> header --unset Authorization

If you are creating form URL-encoded data, a shortcut has been made to avoid having to manually URL-encode everything manually:

        http://my-server.com> form foo=bar baz=1,2,3

        # outputs
        foo=bar&baz=1%2C2%2C3

Response Handling

By default, presto will just dump the response body to the screen after a request is completed. There are additional options, however:

        # dump full request/response to the screen (exactly as transmitted over the wire)
        http://my-server.com> config verbose 1

        # parse the response according to the content-type and use
        # Data::Dumper to display it
        http://my-server.com> config deserialize_response 1

        # use something other than Data::Dumper to dump a parsed
        # response body
        http://my-server.com> config pretty_printer JSON
        http://my-server.com> config pretty_printer Data::Dump

        # send the output to a file (the '>' must not be followed by any white-space!)
        http://my-server.com> GET /some-image.png >some-image.png

Pretty-printing can be especially helpful for making XML or JSON response bodies more human-readable.

When deserialize_response is set, if the content-type of the response is "text/html", the HTML is automatically stripped with HTML::FormatText::WithLinks and displayed as formatted text.

If the request or response body is binary (using a simple heuristic like the -B file-test operator), the output is not printed to STDOUT. Instead, you may want to use output redirection as show above and send the response body to a file.

        http://my-server.com> GET /some-image.jpg >foo.jpg

Persistent Configuration

As demonstrated above, you can use the config command to change the behavior of presto. These configuration options are persisted in a config file specific to the endpoint provided at the command-line and will be reloaded the next time you invoke presto with the same endpoint.

Current valid config keys are:

  • verbose

    Boolean, when enabled, dumps request/response to STDOUT (defaults to "0")

  • deserialize_response

    Boolean, when enabled response body is parsed based on the Content-Type header (defaults to "1")

  • pretty_printer

    Must be one of the supported modules (i.e. Data::Dumper or JSON). Use tab completion to see currently supported values (defaults to "JSON").

  • binmode

    Used to set encoding of STDIN and STDOUT handles (defaults to "utf8")

TODO: provide a means for aliasing endpoints so that configuration is shared across multiple endpoints.

History and Scripting

Just like configuration, command history is maintained separately for each endpoint specified on the command-line and is persisted across sessions (assuming you have a capable Term::Readline library installed). You can interrogate the history using the (surprisingly named) history command. It supports a small subset of the bash history command:

        # dump all history
        http://my-server.com> history

        # dump last 5 entries
        http://my-server.com> history 5

        # delete specific history entries
        http://my-server.com> history -d 4

        # clear history
        http://my-server.com> history -c

Presto also provides a way of saving and replaying bits of your command history. Here are some examples:

        # save all history to script file "my-script"
        http://my-server.com> save my-script

        # save the last 5 history entries
        http://my-server.com> save my-script 5

        # save entries 3-7
        http://my-server.com> save my-script 3..7 

To replay scripts:

        http://my-server.com> source my-script

        # prompt before each command
        http://my-server.com> source -i my-script

Variable interpolation

At times (especially when working with scripts) it might be handy to use elements from a previous response to affect a subsequent request. Anything inside a balanced $(...) will be interpolated for you. For instance, a very contrived example:

        # hypothetical authentication protocal that returns a token in the response headers
        http://my-server.com> POST /auth.json username=jdoe&password=s3cr3t
        {"authenticated":true}

        # see the authentication token
        http://my-server.com> echo $(HEADER[X-Auth-Token])
        2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae

If you need to include that in subsequent request, you can use the "stash" feature:

        # store the value
        http://my-server.com> stash auth-token $(HEADER[X-Auth-Token])

        # use the value later
        http://my-server.com> header X-Auth-Token $(STASH[auth-token])

Those variable substitutions can be used anywhere in a command. HEADER and BODY always refer to the most recent request while the STASH is a persisted for the life of the process.

One useful feature for scripting is to prompt for user input. You can do this by using the PROMPT pseudo-variable. The first set of brackets specify the prompt value. The second (optional) set of brackets specify the initial value. An example:

        # collect the username/password from the user
        http://my-server.com> stash username $(PROMPT[username:])
        http://my-server.com> stash password $(PROMPT[password:])

        # use the stashed values
        http://my-server.com> authorization $(STASH[username]) $(STASH[password])
        http://my-server.com> GET /$(STASH[username])/profile

        # or use a value that was prompted for directly (without stashing it)
        http://my-server.com> GET /products 'created_on=$(PROMPT[Created on (YYYY-MM-DD):])'

        # you can also specify initial values
        http://my-server.com> GET /products 'status=$(PROMPT[Product status:][active])'

You may also specify a local file to use as an argument to a command. An example:

        http://my-server.com> POST /products $(FILE[my-product.xml])

The file is assumed to be in the same encoding as the binmode configuration. If it is using a different character set, you can specify that in a second bracketed parameter:

        http://my-server.com> POST /products $(FILE[my-product.xml][latin-1])

The contents of the file will be slurped, decoded and included as an argument to the command as if you had typed it on the command-line directly.

TODO: Allow data structure references (from STASH or even BODY) to be passed to a POST or PUT command which is then serialized based on the content-type of the request before being sent over the wire.

(EXPERIMENTAL) Data::DPath integration

As an add-on to the variable interpolated described above, you can use dpath expressions to further process the data returned from the REST service. Another very contrived example:

        http://my-server.com> GET /products.json
        [{"id":"1","name":"My Product"},{"id":"2","name":"Another Product"}]

        # issue a request to /product/2.json
        http://my-server.com> GET /product/$(BODY/id[-1]).json
        {"id":2,"name":"Another Product"}

In this example, anything after BODY (including the /) is passed to Data::DPath and the result is then injected in it's place (the target data for BODY being the previous request's response data).

This feature will work on $(STASH) values as well.

CAVEAT EMPTOR

This is beta-quality code and while I use it in my own daily workflow, it is likely riddled with horribly obvious bugs and missing functionality (let alone undocumented features).

ACKNOWLEDGEMENTS

Much of this was inspired by resty which is a rather magical (aka convoluted) set of bash functions (at least for this occassional bash programmer). After attempting to understand and enhance resty, I decided to try my hand at creating something a little more perlish.

A big thank you to Shutterstock Images for allowing me to work on this on company time and release it to the CPAN.

AUTHOR

Brian Phillips <bphillips@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Brian Phillips and Shutterstock Images (http://shutterstock.com).

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.