---
title:  POST /gemfire-api/v1/functions/{functionId}
---

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Execute <%=vars.product_name%> function on entire cluster or on a specified region, members and member groups.

## Resource URL

``` pre
/gemfire-api/v1/functions/{functionId}?[&onRegion=regionname|&onMembers=member1,member2,...,memberN|&onGroups=group1,group2,...,groupN]
```

## Parameters

-   **{functionId}** This required parameter is the name of the function to execute. Place it in the Resource URL, as in the example request: `AddFreeItemToOrders`.
-   **onRegion** This optional parameter specifies the target region for the function. You can only invoke a function on a single region. Substitute the region's name for `regionname` within the sample syntax `onRegion=regionname`.
-   **onMembers** This optional parameter specifies the target members of the function. For multiple members, specify a comma-delimited list of member names, as in the sample `onMembers=member1,member2`.
-   **onGroups** This optional parameter specifies the target groups of the function. For multiple groups, specify a comma-delimited list of group names, as in the sample `onGroups=membergroup1,membergroup2`.
-   **filter** This optional parameter can only be used with the **onRegion** parameter, where the region has a `data-policy` of `PARTITION`. The parameter specifies a list of applicable keys that the function needs to filter on. There are 3 keys in the example Resource URL:

    ``` pre
    http://serverURL/functions/SampleFunction?onRegion=TestPartitionRegion&filter=key1,key2,key3
    ```

-   Any *function arguments* are passed in the request body in JSON format. The content of the arguments can depend on how the function is defined. Use @type to declare argument types and @value for specifying a scalar value. An example set of arguments:

    ``` pre
    [
            {
                 "@type":  "double",
                 "@value": 210
            },
            {
                 "@type":  "org.apache.geode.web.rest.domain.Item",
                 "itemNo":  "599",
                 "description":  "Part X Free on Bumper Offer",
                 "quantity":  "2",
                 "unitprice":  "5",
                 "totalprice":  "10.00"
            }
    ]
    ```

## Example Requests

``` pre
Request Payload: application/json
POST /gemfire-api/v1/functions/AddFreeItemToOrders
Accept: application/json
Content-Type: application/json

[
        {
             "@type":  "double",
             "@value": 210
        },
        {
             "@type":  "org.apache.geode.web.rest.domain.Item",
             "itemNo":  "599",
             "description":  "Part X Free on Bumper Offer",
             "quantity":  "2",
             "unitprice":  "5",
             "totalprice":  "10.00"
        }
]
```

Another example:

``` pre
Request Payload: null

POST /gemfire-api/v1/functions/getDeliveredOrders
Accept: application/json
```

## Example Success Responses

``` pre
Response Payload: null
200 OK
Location:http: //localhost:8080/gemfire-api/v1/functions/AddFreeItemToOrders
```

Another example response:

``` pre
Response Payload: application/json

200 OK
Content-Length: 316
Content-Type: application/json
Location: http://localhost:8080/gemfire-api/v1/functions/getDeliveredOrders
[
    {
         "purchaseOrderNo":  "1121",
         "deliveryDate":  "Thu Feb 20 00:00:00 IST 2014"
    },
    {
         "purchaseOrderNo":  "777",
         "deliveryDate":  "Thu Feb 20 00:00:00 IST 2014"
    },
    {
        ...
    }
]
```

## Error Codes

Status code 500 INTERNAL SERVER ERROR is an error encountered in a server. Check the HTTP response body for a stack trace of the exception. Causes:

-   The Region identified by name (%1$s) could not found!
-   Could not found the specified members in disributed system!
-   no member(s) are found belonging to the provided group(s)!
-   Disributed system does not contain any valid data node to run the specified function!
-   Key is of an inappropriate type for this region!
-   Specified key is null and this region does not permit null keys!
-   Server has encountered low memory condition!
-   Input parameter is null!
-   Could not convert function results into Restful (JSON) format!
-   Function has returned results that could not be converted into Restful (JSON) format!
-   Server has encountered an error while processing function execution!