Introduction

This API within X2Engine, can be accessed via the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root

 index.php/api2

It also:

• Exclusively uses JSON for data input and output
• Tends to use similar URIs for both input and output (distinguishing operations via the request method)
• Uses a variety of server response codes to distinguish error scenarios in the case of an unsuccessful transaction
• Uses the "HTTP Basic Auth" method for authentication

For example, to create a contact, one would send a POST request with its body a JSON-encoded attributes list to the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root

 index.php/api2/Contacts

with the Content-Type header set to application/json, and the request body as (for example):

{"firstName":"John","lastName":"Smith","visibility":1,"email":"johnsmith@example.com"}

If creation of the contact is successful, the server should respond with status code 201 ("Created"), and the response should contain a Location header with the full URL (including protocol) of the newly created contact (in addition to all the attributes of the new contact). If for example the new contact's ID is 123, that URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root would be

 index.php/api2/Contacts/123.json

and a GET request to that URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root would elicit a response from the server whose body contains a JSON-encoded list of attributes.

URI Formats and Terminology

Note, the above example, the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root to which the POST request is sent (to create the contact) is referred to in this documentation as a base URI. Base URIs, when requested using the GET method, return a JSON-encoded array, each entry in the array corresponding to a record and being a dictionary of column:value pairs. So for example, if sending GET to the contacts model base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root, the response would look like this:

[...,{"email": "johnsmith@example.com","firstName": "John","lastName": "Smith",...},...]

Whenever a URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root points to an object or resource uniquely identified with a specific database record, that URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root is referred to as a direct URI. Direct URIs respond to GET requests with JSON-encoded dictionaries of column values for the record as it is in the database. So, the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root in the above example (index.php/api2/Contacts/123.json) would respond with:

{"email": "johnsmith@example.com","firstName": "John","lastName": "Smith",...}

Direct URIs will almost always end in ".json".

Access Credentials

To use the API, you will need to obtain X2Engine API credentials, which include a username and an API key. An X2Engine user with administrative privileges can get or set API keys in the Users module administrator. Any user can authenticate via the API by visiting the Update page for any given user.

Explore the API Using Your Web Browser

Once you have API credentials, you can examine the web API using your web browser by making GET requests to locations within index.php/api2 (simply by typing them into your browser's location bar). You can get a nicer view of the data returned by the server by installing a JSON viewing plugin in your web browser. A recommended plugin for this purpose is JSONView, which is available for Firefox and for Google Chrome (it's an unofficial port, but the developer of the API and author of this article uses it).

Example 1: hello, world

Try visiting the following URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root within X2Engine:

 index.php/api2/appInfo.json

Initially you will be prompted to enter the username and password to complete authentication; enter the API key corresponding to the user in the password field. The above URL should respond with a JSON string containing some basic info about the X2Engine application.

Example 2: direct access

You can get the ID of any given account record by going to it inside X2Engine as you normally would and examining the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root. It should generally look something like this:

 index.php/accounts/32

or:

 index.php/accounts/id/32

In both of the above examples, the primary key value (id) of the record in question is 32. To view it in the API:

 index.php/api2/Accounts/32.json

Note how in the API, the first letter of "Accounts" in the direct URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root is capitalized. This is because active record data in the API is accessed not via specifying the module containing the active record class, or to which the class corresponds, but by specifying the actual class name to use when accessing (or querying) data.

Example 3: querying

 index.php/api2/Actions?_order=-id&_limit=3

This will show you the last 3 action records (i.e. emails, call logs, to-do's) created in the system (which the current acting API user has permission to view), in descending order of their primary key values (column "id"). If you have no action records in your system, you should receive an empty array.

Prerequisites for API Applications

When writing an application to interface with X2Engine via the API, it is required or strongly recommended that your language/coding environment of choice:

• Have a JSON parsing and encoding library available
• Have a library for making HTTP requests which can:
  • Set request headers
  • Parse response headers and read the response status code
  • Natively support requests using HTTP Basic Auth for access
  • Read responses even when the response code is not in the "success" category (2xx)
  • Make POST, PATCH/PUT and DELETE requests
• Can access the network

Many high-level languages, such as Perl, PHP, Python and Ruby, meet these requirements. The specific usage of these languages is beyond the scope of this article; you will need to refer to the documentation of the library/libraries in use.

It is expected in the near future that a growing number of official API access classes (each in a different programming language) will be available for quick and easy development of API applications.

Authentication

As stated before, the API uses "HTTP Basic" authorization. Many HTTP client libraries will have native methods of setting headers for HTTP basic auth. It is recommended that you use such a method for authentication and read the relevant documentation, rather than setting headers manually, as that will save time and more likely lead to quicker success.

In all other cases, to authenticate and access the API using this method, each request must include the Authorization header. To compose the header, first combine the username and API key into a single string with a colon, as:

 {username}:{userKey}

Next, obtain the string in Base-64 encoding. For example, username:password in base 64 is dXNlcjpwYXNzd29yZA==. Thus, the resulting header would look like this:

 Authorization: Basic dXNlcjpwYXNzd29yZA==

See also the the Wikipedia article on this topic.

Note: because headers are sent without any built-in encryption, it is highly recommended that you use the API over HTTPS (HTTP encrypted using TLS[[wikipedia:Transport Layer Security]] a method of connecting to a remote network host that encrypts traffic on any given network protocol that uses it.), if available, or make API requests only within a network where packets are not easily intercepted.

Model-centric API Functions

Most of the modules in X2Engine (i.e. Contacts) will each have a corresponding active record model. This model is what is customized whenever adding a custom field. It is essentially a PHP class that is a child of X2Model (see: X2Model and Dynamic Fields for more information). Almost all API-based functions involving such data objects will contain the name of that class in the URL, i.e.

 index.php/api2/Accounts
 index.php/api2/Contacts/135/Actions
 index.php/api2/Contacts/112.json

In general, the base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root for functions pertaining to models is

 index.php/api2/{_class} 

where {_class} is the class. The direct URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root is generally:

 index.php/api2/{_class}/{_id}.json

where {_id} is the ID of the record to access.

Basic Model Types

As of this writing, X2Engine by default has the following model classes that are fully supported in the API — meaning, all or nearly all of the most essential functionality that is possible in X2Engine via a web browser, in terms of manipulation of persistent data storage, is also possible via the API.

• Accounts
• BugReports
• Contacts
• Campaign
• Opportunity
• Product
• Services

Additionally, any custom modules will also have corresponding active record models fully supported by the API. This should usually be the same name as the module, but without spaces and the first letter always capitalized. If in doubt, to find the model class corresponding to a given module (i.e. a custom module), look in the "models" sub-directory of that module. The name of the file excluding the extension (.php) should be the name of the class. For instance, in the file protected/modules/contacts/models/Contacts.php there should be the following line:

class Contacts extends X2Model {

Partially-supported Models

Manipulation of data using the following models (or certain aspects of the following models) is not fully supported in the API as of this writing — meaning, while most operations are possible, some important functionality is not yet possible:

Creating, Viewing Updating and Deleting Records

To create a record, perform a POST request to the base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root for the model, i.e.

 index.php/api2/Contacts

to create a contact. As mentioned in the example in the #Introduction, the body of the request must be a JSON-encoded library of attributes to set in the model, and the Content-Type header must be set to application/json.

To view, update or delete a record, first determine its direct URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root within the API, as set in the Location header if creation was successful, or as determined via its class and id, i.e.

 index.php/api2/Contacts/33.json

to specify a contact record with its id equal to 33.

To update a record, send a PUT or PATCH request to a direct URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root, and set the body and Content-Type header as one would in a POST request to create such a record. Finally, to delete the record, send a DELETE request to that same URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root. It is not necessary in the case of deletion to include a body or set the Content-Type header.

Working With Associated Actions

The Actions model is unique in that it can be "associated" with almost any other type of model record. Actions records comprise all "history" items on any given record, i.e. emails, calls logged, notes, calendar events and also plain actions. Actions that have an association with another model can be used via clean URIs that point to "within" the associated model.

URI Formats

To view/query all actions associated with an active record model of class {_class} and id {_id}, use the following base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root:

 index.php/api2/{_class}/{_id}/Actions

For instance, one could find all actions, including emails, on contact id=1233, via:

 index.php/api2/Contacts/1233/Actions

To view an individual action of id {_actionId}, one can use this direct URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root:

 index.php/api2/{_class}/{_id}/Actions/{_actionId}.json

Creating, Updating and Deleting Actions

Similar to the the basic model access API function, PATCH, POST, PUT and DELETE requests can be sent to associated action URIs to create/modify/delete records just as those URIs can also be used to view data. POST to index.php/api2/{_class}/{_id}/Actions creates a new action associated with model record of class {_class} and id {_id}, and PATCH/PUT/DELETE requests to the "individual view" URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root index.php/api2/{_class}/{_id}/Actions/{_actionId}.json can be used to modify/delete an existing associated action record.

Querying Data

Almost any "base" URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root, which can be used for accessing all records of a type or for creating new records of a type, can also be used for querying records of that type. Responses to queries (and GET requests to these URIs in general) will always be JSON-encoded arrays of records, each record represented as an attribute dictionary.

Options for searching, as well as attributes to match column values against (for filtering), are all specified as query parameters (a.k.a. "get parameters"). The search options, to protect against name collisions with column names, each have names that begin with an underscore, i.e. _order.

General Search Option Parameters

In queries, one can use a variety of advanced options that include sorting, pagination, partial matching, and in some cases tags.

Adding Query Parameters

Appending option parameters proceeds as it would for any script that can receive URL-encoded variables via the request: follow the base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root with a question mark, and delineate [name]=[value] parameter declarations with ampersands (note: this might be different, depending on your web server's configuration, but the nearly-ubiquitous default is ampersand-delineation). For example:

 index.php/api2/Contacts?_limit=10&firstName=Harry&lastName=P%25&_partial=1&_escape=0&_order=+lastName

This will return the first ten contacts out the list of contacts having first name "Harry" and last name beginning with "P", sorted alphabetically by last name.

Searching For Models By Tag

In addition to the _tags search option, there is a "pretty" dedicated base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root format for tag searching:

 index.php/api2/tags/{_tags}/{_class}

So, for instance, to find all contacts with the tags "#customer" and "#important":

 index.php/api2/tags/customer,important/Contacts

The above is equivalent to

 index.php/api2/Contacts?_tags=customer,important

Note, additional search parameters can also be included. For instance, to return the first ten most recently updated contacts with the above tags:

 index.php/api2/tags/customer,important/Contacts?_order=-lastUpdated&_limit=10

The reason for this is to express tags as categories, and thus in a loose sense "folders" in which one would find records.

Model Metadata API Functions

There is "structural" metadata that one can retrieve through the API to more effectively determine how to proceed with future API transactions. There are also some functions in the API that pertain to functionality associated with model records, but do not modify data within the records themselves, and create associated metadata.

Model Fields

One can access field metadata for a given model class by using the following base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root (which supports querying):

 index.php/api2/{_class}/fields

One can directly access the metadata of a field by its name via the following direct URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root format:

 index.php/api2/{_class}/fields/{_fieldName}.json

For instance, this URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root

 index.php/api2/Contacts/fields/leadSource.json

would respond with:

{"id":"88", "modelName":"Contacts", "fieldName":"leadSource", "attributeLabel":"Lead Source", "modified":"0", "custom":"0", "type":"dropdown", "required":"0", "uniqueConstraint":"0", "safe":"1", "readOnly":"0", "linkType":"103", "searchable":"0", "relevance":"", "isVirtual":"0","defaultValue":null,"keyType":null}

Field-Level Permissions

A GET to the following will respond with a dictionary of active record model attributes, each value corresponding to field-level access permissions for that field granted the current acting API user.

 index.php/api2/{_class}/fieldPermissions.json

For example, as the default administrator, for model Contacts, getting the following:

 index.php/api2/Accounts/fieldPermissions.json

will respond with:

{"leadtype":2, "leadSource":2, "leadstatus":2, "leadDate":2, "leadscore":2, "interest":2, "dealvalue":2, "closedate":2, "rating":2, "dealstatus":2, "name":2, "nameId":1, "id":1, "website":2, "type":2, "visibility":2, "annualRevenue":2, "phone":2, "tickerSymbol":2, "address":2, "city":2, "state":2, "country":2, "zipcode":2, "parentAccount":2, "primaryContact":2, "employees":2, "assignedTo":2, "createDate":1, "description":2, "lastUpdated":1, "lastActivity":1, "updatedBy":1}

For each of these entries, the number associated with the field indicates the following:

Field Dropdowns

Some fields, i.e. lead source in contacts, are of type "dropdown"; their content is intended to be either blank, or an option in a static list. Dropdown menus can be queried at base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root

 index.php/api2/dropdowns

Dropdown fields can also be directly accessed via

 index.php/api2/dropdowns/{_id}.json

To find out if a field is of type dropdown, and which dropdown menu it uses: the value for type in the field's metadata record should be "dropdown", and the linkType field should contain the dropdown's ID.

Note, for convenience's sake the "options" field won't be returned verbatim as the raw JSON (that's how the options are stored). Rather, that field will be decoded into a sub-library of the overall object JSON. So, this URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root

 index.php/api2/dropdowns/103.json

would return:

{"id":"103", "name":"Lead Source", "options":{"None":"None", "Google":"Google", "Facebook":"Facebook", "Walk In":"Walk In"}, "multi":"0", "parent":null, "parentVal":null}

Relationships

It is possible to create, view, and delete relationships between supported API models in X2Engine via the API.

URI Formats

Relations functionality is in general accessed within the following base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root:

 index.php/api2/{_class}/{_id}/relationships

So, to view all relationships going to or from account 131:

 index.php/api2/Accounts/131/relationships

To view the contents (related model class and ID) of a specific relationship on the account (let's say the relation record has its id=304281 for instance):

 index.php/api2/Accounts/131/relationships/304281.json

The Relationships active record model has the following attributes that can be used in queries:

id

Unique numeric identifier for the relationship

firstType, firstId

The model class and record ID at one end of the relationship, respectively

secondType, secondId

The model class and record ID at the other end of the relationship, respectively

For instance, to find all outgoing relationships with Accounts to contact id=126:

 index.php/api2/Contacts/126/relationships?secondType=Accounts

Adding/Removing Relationships

To create a new relationship, sent POST to the "all relationships" URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root index.php/api2/{_class}/{_id}/relationships.

To remove a relationship, send DELETE to the individual viewing URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root of the record, i.e. index.php/api2/Accounts/131/relationships/304281.json in the earlier example.

Tags

All basic, fully-supported models in X2Engine should support tagging. Tags cannot be individually modified, but can only be created, viewed, queried and removed, in order to enforce preservation of the important metadata such as who added the tag and at what date.

URI Formats

Tags on a given model record can be retrieved via GET at the following base URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root:

 index.php/api2/{_class}/{_id}/tags

The response should be a flat array of tag names. For example, if account 51 has tags "#customer" and "#local", sending GET to the following URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root

 index.php/api2/Accounts/51/tags

will yield:

["#customer","#local"]

To view more extensive metadata of the tag, i.e. who added the tag and at what date:

 index.php/api2/{_class}/{_id}/tags/{_tagName}.json

i.e.

 index.php/api2/Accounts/51/tags/local.json

The above will return a dictionary of x2_tags column names and values. Note, the tag name in the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root must either exclude the preceding hash mark or include it via its corresponding URL encoding sequence, %23. This is because the hash mark is a special character in the HTTP protocol and will interfere with proper resolution of the URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root. Using the above example:

 index.php/api2/Accounts/51/tags/%23local.json

That URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root will return the exact same data as the previous URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root; they are considered equivalent.

Adding Tags to a Record

Adding tags also utilizes that same URI[[wikipedia:Uniform Resource Identifier]]: The part of a URL that identifies the resource on the server to be accessed. In the context of the API, this refers to the relative path within the web server based in the web root of X2Engine, i.e. ''index.php/api2/Contacts/324.json'' as opposed to the full URL, which begins with the protocol (i.e. "http") and might also contain a path relative to the web site's document root scheme as with viewing tags. To add one or more tags, send them as string elements in a flat JSON-encoded array via POST to that location. For example, to use the previous example, one can apply the tags "#customer" and "#local" from "record 51" to record 52 by POST-ing the same JSON returned from a GET at:

 index.php/api2/Accounts/51/tags

to:

 index.php/api2/Accounts/52/tags

Removing Tags

To delete a tag, send a DELETE request to the direct viewing location of the tag. So, for instance, to delete "#local" from account 51, send DELETE to index.php/api2/Accounts/51/tags/local.json

Interpreting Server Responses

HTTP Response Codes

It is important to be able to read and interpret status codes (and for that matter, response headers) because in all success scenarios, the API does not respond with data envelopes. By this it is meant the act of wrapping a data model's attributes inside another array containing metadata about the status of the request. This is in effort to streamline and make more elegant code that handles response data. It is also for consistency's sake. A contacts model accessed as a resource object with name ending with .json is expected to be that contact, and not rather an array with server response info or other metadata.

In general, the meanings of response codes closely or exactly follow the formal definitions as defined in RFC2616, as well as the informal definitions of unconventional status codes (See wikipedia:List of HTTP status codes). The following table lists each of the possible status codes that the API will respond with, the contexts in which they would appear, and what they indicate.

Error Objects

In all error responses produced by the API and not by the server itself, the body of the response will be a JSON containing metadata about the error and the response. This is for compatibility with less-than-satisfactory client libraries which cannot read the actual response code or headers, but might be able to read the response body when the code is not in the success (2XX) range. In such cases, the response will be a JSON-encoded object with at least the following properties:

In some cases, the response JSON may include the following additional properties: