NAME
    RT::Extension::REST2 - Adds a modern REST API to RT under /REST/2.0/

INSTALLATION
    perl Makefile.PL
    make
    make install
        May need root permissions

    Edit your /opt/rt4/etc/RT_SiteConfig.pm
        Add this line:

            Plugin('RT::Extension::REST2');

    Clear your mason cache
            rm -rf /opt/rt4/var/mason_data/obj

    Restart your webserver

USAGE
  Tutorial
    To make it easier to authenticate to REST2, we recommend installing
    RT::Authen::Token. Visit "Logged in as ___" -> Settings -> Auth Tokens.
    Create an Auth Token, give it any description (such as "REST2 with
    curl"). Make note of the authentication token it provides to you.

    For other authentication options see the section "Authentication
    Methods" below.

   Authentication
    Run the following in a terminal, filling in XX_TOKEN_XX from the auth
    token above and XX_RT_URL_XX with the URL for your RT instance.

        curl -H 'Authorization: token XX_TOKEN_XX' 'XX_RT_URL_XX/REST/2.0/queues/all'

    This does an authenticated request (using the Authorization HTTP header
    with type token) for all of the queues you can see. You should see a
    response, typical of search results, like this:

        {
           "total" : 1,
           "count" : 1,
           "page" : 1,
           "per_page" : 20,
           "items" : [
              {
                 "type" : "queue",
                 "id" : "1",
                 "_url" : "XX_RT_URL_XX/REST/2.0/queue/1"
              }
           ]
        }

    This format is JSON, which is a format for which many programming
    languages provide libraries for parsing and generating.

    (If you instead see a response like {"message":"Unauthorized"} that
    indicates RT couldn't process your authentication token successfully;
    make sure the word "token" appears between "Authorization:" and the auth
    token that RT provided to you)

   Following Links
    You can request one of the provided _urls to get more information about
    that queue.

        curl -H 'Authorization: token XX_TOKEN_XX' 'XX_QUEUE_URL_XX'

    This will give a lot of information, like so:

        {
           "id" : 1,
           "Name" : "General",
           "Description" : "The default queue",
           "Lifecycle" : "default",
           ...
           "CustomFields" : {},
           "_hyperlinks" : [
              {
                 "id" : "1",
                 "ref" : "self",
                 "type" : "queue",
                 "_url" : "XX_RT_URL_XX/REST/2.0/queue/1"
              },
              {
                 "ref" : "history",
                 "_url" : "XX_RT_URL_XX/REST/2.0/queue/1/history"
              },
              {
                 "ref" : "create",
                 "type" : "ticket",
                 "_url" : "XX_RT_URL_XX/REST/2.0/ticket?Queue=1"
              }
           ],
        }

    Of particular note is the _hyperlinks key, which gives you a list of
    related resources to examine (following the
    <https://en.wikipedia.org/wiki/HATEOAS> principle). For example an entry
    with a ref of history lets you examine the transaction log for a record.
    You can implement your REST API client knowing that any other hypermedia
    link with a ref of history has the same meaning, regardless of whether
    it's the history of a queue, ticket, asset, etc.

    Another ref you'll see in _hyperlinks is create, with a type of ticket.
    This of course gives you the URL to create tickets *in this queue*.
    Importantly, if your user does *not* have the CreateTicket permission in
    this queue, then REST2 would simply not include this hyperlink in its
    response to your request. This allows you to dynamically adapt your
    client's behavior to its presence or absence, just like the web version
    of RT does.

   Creating Tickets
    Let's use the _url from the create hyperlink with type ticket.

    To create a ticket is a bit more involved, since it requires providing a
    different HTTP verb (POST instead of GET), a Content-Type header (to
    tell REST2 that your content is JSON instead of, say, XML), and the
    fields for your new ticket such as Subject. Here is the curl invocation,
    wrapped to multiple lines for readability.

        curl -X POST
             -H "Content-Type: application/json"
             -d '{ "Subject": "hello world" }'
             -H 'Authorization: token XX_TOKEN_XX'
                'XX_TICKET_CREATE_URL_XX'

    If successful, that will provide output like so:

        {
            "_url" : "XX_RT_URL_XX/REST/2.0/ticket/20",
            "type" : "ticket",
            "id"   : "20"
        }

    (REST2 also produces the status code of 201 Created with a Location
    header of the new ticket, which you may choose to use instead of the
    JSON response)

    We can fetch that _url to continue working with this newly-created
    ticket. Request the ticket like so (make sure to include the -i flag to
    see response's HTTP headers).

        curl -i -H 'Authorization: token XX_TOKEN_XX' 'XX_TICKET_URL_XX'

    You'll first see that there are many hyperlinks for tickets, including
    one for each Lifecycle action you can perform, history, comment,
    correspond, etc. Again these adapt to whether you have the appropriate
    permissions to do these actions.

    Additionally you'll see an ETag header for this record, which can be
    used for conflict avoidance (<https://en.wikipedia.org/wiki/HTTP_ETag>).
    We'll first try updating this ticket with an *invalid* ETag to see what
    happens.

   Updating Tickets
    For updating tickets we use the PUT verb, but otherwise it looks much
    like a ticket creation.

        curl -X PUT
             -H "Content-Type: application/json"
             -H "If-Match: invalid-etag"
             -d '{ "Subject": "trial update" }'
             -H 'Authorization: token XX_TOKEN_XX'
                'XX_TICKET_URL_XX'

    You'll get an error response like {"message":"Precondition Failed"} and
    a status code of 412. If you examine the ticket, you'll also see that
    its Subject was not changed. This is because the If-Match header advises
    the server to make changes *if and only if* the ticket's ETag matches
    what you provide. Since it differed, the server refused the request and
    made no changes.

    Now, try the same request by replacing the value "invalid-etag" in the
    If-Match request header with the real ETag you'd received when you
    requested the ticket previously. You'll then get a JSON response like:

        ["Ticket 1: Subject changed from 'hello world' to 'trial update'"]

    which is a list of messages meant for displaying to an end-user.

    If you GET the ticket again, you'll observe that the ETag header now has
    a different value, indicating that the ticket itself has changed. This
    means if you were to retry the PUT update with the previous (at the
    time, expected) ETag you would instead be rejected by the server with
    Precondition Failed.

    You can use ETag and If-Match headers to avoid race conditions such as
    two people updating a ticket at the same time. Depending on the
    sophistication of your client, you may be able to automatically retry
    the change by incorporating the changes made on the server (for example
    adding time worked can be automatically be recalculated).

    You may of course choose to ignore the ETag header and not provide
    If-Match in your requests; RT doesn't require its use.

   Summary
    RT's REST2 API provides the tools you need to build robust and dynamic
    integrations. Tools like ETag/If-Match allow you to avoid conflicts such
    as two people taking a ticket at the same time. Using JSON for all data
    interchange avoids problems caused by parsing text. Hypermedia links
    inform your client application of what the user has the ability to do.

    Careful readers will see that, other than our initial entry into the
    system, we did not *generate* any URLs. We only *followed* links, just
    like you do when browsing a website on your computer. We've better
    decoupled the client's implementation from the server's REST API.
    Additionally, this system lets you be informed of new capabilities in
    the form of additional hyperlinks.

  Endpoints
    Currently provided endpoints under /REST/2.0/ are described below.
    Wherever possible please consider using _hyperlinks hypermedia controls
    available in response bodies rather than hardcoding URLs.

   Tickets
        GET /tickets?query=<TicketSQL>
            search for tickets using TicketSQL

        GET /tickets?simple=1;query=<simple search query>
            search for tickets using simple search syntax

        POST /tickets
            search for tickets with the 'query' and optional 'simple' parameters

        POST /ticket
            create a ticket; provide JSON content

        GET /ticket/:id
            retrieve a ticket

        PUT /ticket/:id
            update a ticket's metadata; provide JSON content

        DELETE /ticket/:id
            set status to deleted

        POST /ticket/:id/correspond
        POST /ticket/:id/comment
            add a reply or comment to the ticket

        GET /ticket/:id/history
            retrieve list of transactions for ticket

   Transactions
        GET /transactions?query=<JSON>
        POST /transactions
            search for transactions using L</JSON searches> syntax

        GET /ticket/:id/history
        GET /queue/:id/history
        GET /queue/:name/history
        GET /asset/:id/history
        GET /user/:id/history
        GET /user/:name/history
        GET /group/:id/history
            get transactions for record

        GET /transaction/:id
            retrieve a transaction

   Attachments and Messages
        GET /attachments?query=<JSON>
        POST /attachments
            search for attachments using L</JSON searches> syntax

        GET /transaction/:id/attachments
            get attachments for transaction

        GET /attachment/:id
            retrieve an attachment

   Queues
        GET /queues/all
            retrieve list of all queues you can see

        GET /queues?query=<JSON>
        POST /queues
            search for queues using L</JSON searches> syntax

        POST /queue
            create a queue; provide JSON content

        GET /queue/:id
        GET /queue/:name
            retrieve a queue by numeric id or name

        PUT /queue/:id
        PUT /queue/:name
            update a queue's metadata; provide JSON content

        DELETE /queue/:id
        DELETE /queue/:name
            disable queue

        GET /queue/:id/history
        GET /queue/:name/history
            retrieve list of transactions for queue

   Assets
        GET /assets?query=<JSON>
        POST /assets
            search for assets using L</JSON searches> syntax

        POST /asset
            create an asset; provide JSON content

        GET /asset/:id
            retrieve an asset

        PUT /asset/:id
            update an asset's metadata; provide JSON content

        DELETE /asset/:id
            set status to deleted

        GET /asset/:id/history
            retrieve list of transactions for asset

   Catalogs
        GET /catalogs/all
            retrieve list of all catalogs you can see

        GET /catalogs?query=<JSON>
        POST /catalogs
            search for catalogs using L</JSON searches> syntax

        POST /catalog
            create a catalog; provide JSON content

        GET /catalog/:id
        GET /catalog/:name
            retrieve a catalog by numeric id or name

        PUT /catalog/:id
        PUT /catalog/:name
            update a catalog's metadata; provide JSON content

        DELETE /catalog/:id
        DELETE /catalog/:name
            disable catalog

   Users
        GET /users?query=<JSON>
        POST /users
            search for users using L</JSON searches> syntax

        POST /user
            create a user; provide JSON content

        GET /user/:id
        GET /user/:name
            retrieve a user by numeric id or username

        PUT /user/:id
        PUT /user/:name
            update a user's metadata; provide JSON content

        DELETE /user/:id
        DELETE /user/:name
            disable user

        GET /user/:id/history
        GET /user/:name/history
            retrieve list of transactions for user

   Groups
        GET /groups?query=<JSON>
        POST /groups
            search for groups using L</JSON searches> syntax

        GET /group/:id
            retrieve a group (including its members)

        GET /group/:id/history
            retrieve list of transactions for group

   Custom Fields
        GET /customfields?query=<JSON>
        POST /customfields
            search for custom fields using L</JSON searches> syntax

        GET /customfield/:id
            retrieve a custom field

   Custom Roles
        GET /customroles?query=<JSON>
        POST /customroles
            search for custom roles using L</JSON searches> syntax

        GET /customrole/:id
            retrieve a custom role

   Miscellaneous
        GET /
            produces this documentation

        GET /rt
            produces system information

  JSON searches
    Some resources accept a basic JSON structure as the search conditions
    which specifies one or more fields to limit on (using specified
    operators and values). An example:

        curl -si -u user:pass https://rt.example.com/REST/2.0/queues -XPOST --data-binary '
            [
                { "field":    "Name",
                  "operator": "LIKE",
                  "value":    "Engineering" },

                { "field":    "Lifecycle",
                  "value":    "helpdesk" }
            ]
        '

    The JSON payload must be an array of hashes with the keys field and
    value and optionally operator.

    Results are returned in the format described below.

  Example of plural resources (collections)
    Resources which represent a collection of other resources use the
    following standard JSON format:

        {
           "count" : 20,
           "page" : 1,
           "per_page" : 20,
           "total" : 3810,
           "items" : [
              { … },
              { … },
              …
           ]
        }

    Each item is nearly the same representation used when an individual
    resource is requested.

  Paging
    All plural resources (such as /tickets) require pagination, controlled
    by the query parameters page and per_page. The default page size is 20
    items, but it may be increased up to 100 (or decreased if desired). Page
    numbers start at 1.

  Authentication Methods
    Authentication should always be done over HTTPS/SSL for security. You
    should only serve up the /REST/2.0/ endpoint over SSL.

   Basic Auth
    Authentication may use internal RT usernames and passwords, provided via
    HTTP Basic auth. Most HTTP libraries already have a way of providing
    basic auth credentials when making requests. Using curl, for example:

        curl -u 'username:password' /path/to/REST/2.0

   Token Auth
    You may use the RT::Authen::Token extension to authenticate to the REST
    2 API. Once you've acquired an authentication token in the web
    interface, specify the Authorization header with a value of "token" like
    so:

        curl -H 'Authorization: token …' /path/to/REST/2.0

    If the library or application you're using does not support specifying
    additional HTTP headers, you may also pass the authentication token as a
    query parameter like so:

        curl /path/to/REST/2.0?token=…

   Cookie Auth
    Finally, you may reuse an existing cookie from an ordinary web session
    to authenticate against REST2. This is primarily intended for
    interacting with REST2 via JavaScript in the browser. Other REST
    consumers are advised to use the alternatives above.

  Conditional requests (If-Modified-Since, If-Match)
    You can take advantage of the Last-Modified headers returned by most
    single resource endpoints. Add a If-Modified-Since header to your
    requests for the same resource, using the most recent Last-Modified
    value seen, and the API may respond with a 304 Not Modified. You can
    also use HEAD requests to check for updates without receiving the actual
    content when there is a newer version. You may also add an
    If-Unmodified-Since header to your updates to tell the server to refuse
    updates if the record had been changed since you last retrieved it.

    ETag, If-Match, and If-None-Match work similarly to Last-Modified,
    If-Modified-Since, and If-Unmodified-Since, except that they don't use a
    timestamp, which has its own set of tradeoffs. ETag is an opaque value,
    so it has no meaning to consumers (unlike timestamps). However,
    timestamps have the disadvantage of having a resolution of seconds, so
    two updates happening in the same second would produce incorrect
    results, whereas ETag does not suffer from that problem.

  Status codes
    The REST API uses the full range of HTTP status codes, and your client
    should handle them appropriately.

AUTHOR
    Best Practical Solutions, LLC <modules@bestpractical.com>

BUGS
    All bugs should be reported via email to
    bug-RT-Extension-REST2@rt.cpan.org
    <mailto:bug-RT-Extension-REST2@rt.cpan.org> or via the web at
    rt.cpan.org
    <http://rt.cpan.org/Public/Dist/Display.html?Name=RT-Extension-REST2>.

LICENSE AND COPYRIGHT
    This software is Copyright (c) 2015-2017 by Best Practical Solutions,
    LLC.

    This is free software, licensed under:

    The GNU General Public License, Version 2, June 1991