K2 Services provide RESTful web services (REST) endpoints for a portion of the SourceCode.Workflow.Client APIs.
The SourceCode.Workflow.Client Namespace documentation contains additional information on the underlying classes, properties, methods and sample code. This namespace can be referenced for additional information when utilizing the REST endpoints.
Developers familiar with using the SourceCode.Workflow.Client APIs as locally referenced resources will be immediately productive accessing these same resources via REST endpoints. However, it is not necessary to have prior knowledge of the SourceCode.Workflow.Client namespace to use K2 Services REST endpoints. The information in this section provides full details on all the methods available for the services including examples to help you get started.
For information on how to configure K2 Services for Claims Authentication support, go to KB001426
The sample code provided as a demonstation is written for use with Web based forms. Sample code for Windows based forms will be available in a future release fo the Developer's Reference
Watch a short video on how to use the K2 REST and WCF Services (Length 13 minutes)
K2 Services REST endpoints provide standard URIs for interacting with the available data and operations. These topics will help in the construction of the appropriate URI for the desired operation.
Core Service
Identity Service
Task Service
Worklist Service
Process Service
Developers who wish to build applications that use RESTful services while interacting with processes, worklists and user information in a similar fashion to the K2 Workflow Client API will want to utilize the Worklist, Process, Identity and Core services, commonly referred to as “Workflow Client”. You will find the Workflow Client services configured by default as the REST.svc endpoint.
Developers who wish to build applications that use RESTful services to access and update a user’s task list, optimized for low bandwidth and offline batch processing scenarios, such as mobile devices, will want to utilize the Task, Identity and Core services, commonly referred to as “Sync”. You will find the Sync services configured by default at the SyncREST.svc endpoint.
The K2 REST Services uses the following standard HTTP status codes.
Different languages and platforms handle HTTP status codes differently. Ensure that sufficient error handling is present for these status codes.
Successful calls which have no return value information will return a <success> element to the client along with the HTTP 200 (OK) response. NOTE: Some asynchronous calls will not provide a return to the client depending on the browser or web request tool being used. In these cases, no return data can indicate success.
<?xml version="1.0" encoding="utf-8"?>
<success xmlns="http://schemas.k2.com/api/framework"/>
Unsuccessful calls will return an <Failure> element to the client along with the appropriate HTTP error response. The error message contains useful information for debugging, regarding the error that occurred on the server. Any call to the server may return this element.
<?xml version="1.0" encoding="utf-8"?>
<Failure ID="0" Code="-1" xmlns="http://schemas.k2.com/framework/d1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Message>25223 Process K2 Examples\Order Process not found</Message>
<Description>client-failure</Description>
</Failure>
K2 Services utilize the capabilities of the Workflow Client Criteria framework to enable filtering and sorting results for REST endpoints.
The Worklist/Items and Task/Items GET methods support the filterXml={filterXml} query option while the Worklist/Items/Filtered and Task/Items/Filtered POST methods support the filter XML in the request body.
The filterXml query option takes a single string parameter which is the filter represented as XML.
GET /K2Services/REST.svc/Worklist/Items?filterXml=<Criteria xmlns="http://schemas.k2.com/worklist/d1"><Filter Field="ProcessFolio" Comparison="Like" ValueType="String">Demo</Filter><Sort Field="ProcessStartDate" Order="Descending" /></Criteria>
GET /K2Services/REST.svc/Task/Items?filterXml=<Criteria xmlns="http://schemas.k2.com/worklist/d1"><Filter Field="ProcessFolio" Comparison="Like" ValueType="String">Demo</Filter><Sort Field="ProcessStartDate" Order="Descending" /></Criteria>
The filter XML can be built using the same techniques as using the SourceCode.Workflow.Client.WorklistCriteria classes, properties and enumerations. The structure of the filter XML consists of a Criteria node with zero or more Filter and/or zero or more Sort nodes.
The order of the attributes does not matter.
<Criteria xmlns="http://schemas.k2.com/worklist/d1"
ManagedUser="{optional}"
Platform="{optional}">
<!-- Zero or more of -->
<Filter Comparison="{valid WCCompare value: Equal, NotEqual, Less, Greater, LessOrEqual, GreaterOrEqual, Like, NotLike}"
Field="{valid WCField value}"
Logical="{valid WCLogical value: And, Or, AndBracket, OrBracket, StartBracket, EndBracket}"
SubField="{optional, valid subfield to compare}"
ValueType="{Boolean, Date, Decimal, Double, Integer, Long, String, Binary}">{Filter Value}</Filter>
<!-- Zero or more of -->
<Sort Field="{valid WCField value}"
SubField="{optional, valid subfield to compare}"
Order="{optional, valid WCSortOrder value: Ascending (default/omitted), Descending}" />
</Criteria>
There are several namespaces used by the services.
| Namespace | Purpose |
|---|---|
| http://schemas.k2.com/framework/d1 | Contains contracts for error and success messages |
| http://schemas.k2.com/core/d1 | Contains contracts for basic system functionality |
| http://schemas.k2.com/user/d1 | Contains contracts for user retrieval |
| http://schemas.k2.com/task/d1 | Contains contracts for task retrieval and updating |
| http://schemas.k2.com/worklist/d1 | Contains contracts for worklist retrieval and updating |
| http://schemas.k2.com/process/d1 | Contains contracts for process retrieval and updating |
| http://schemas.k2.com/activity/d1 | Contains contracts for activity retrieval and updating |
| http://schemas.k2.com/event/d1 | Contains contracts for event retrieval and updating |
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