Filter Configurations

The idea behind filter configurations is to create a general filter structure which an author would implement according to the requirements of the target system. The underlying implementation (pfx-api, pxf-rest) would use such a filter and query the target system accordingly.

Limitations

Filter representation is now limited to the HTTP protocol. Within the protocol, the filter may appear in the following parts:

URI (as query params)
HTTP headers
Request body

The location and representation of the filter is defined by author of the configuration scheme.

Definition

Filter configurations are represented in the XML format so that it is easier to work with the transformer function. This is a sample filter configuration:

<filters>
    <filter>
        <name>sap-body-filter</name>              // name of the config, must be unique
        <type>body</type>                         // type of the filter. Might be: body, header, uri, pricefx
        <transformer>
            <language>groovy</language>           // language used for the script below. Supported: groovy, simple, constant
            <script>                              // transformer function definition
                def res = [:]
                if (!headers['filter-resultFields']?.empty){ res.put('fields', headers['filter-resultFields']) }
                if (!headers['filter-sortBy']?.empty){ res.put('sort', headers['filter-sortBy'].join('-')) }
                if (headers['filter-condition'] != null){ res.put('condition', headers['filter-condition'].criteria.collect{it -> it.fieldName + it.operator.sign + it.value}.join(',')) }
                return res
            </script>
        </transformer>
    </filter>
</filters>

Implementation Notes

script is subject to Sandboxing – not all features are enabled. For details see Groovy Sandbox.

If the type is pricefx, the filter can only be used in the pfx-api component. In such case, the transformer element is not required. The filter will appear in the request body as JSON.
- type = header – Filter will appear in the request headers.
- type = uri – Filter will appear in the request URL as query parameters.
If the type is body, header or uri, the filter can only be used in the pfx-rest component. According to the selected type, the filter will appear in:
- type = body – Filter will appear in the request body as JSON.
- type = header – Filter will appear in the request headers.
- type = uri – Filter will appear in the request URL as query parameters.
The script section describes the transformer function which is used to transform the general filter structure into a system-specific filter. There are several limitations and notes:
- The script must be compilable and must always return a value.
- The returned data type must be Map.
- Available properties within the script are:

Name	Type	Key	Data type

Name	Type	Key	Data type
Result fields	header	headers['filter-resultFields']	List
Sort by	header	headers['filter-sortBy']	List
Condition	header	headers['filter-condition']	Object

Using Languages

You can use language in the <transformer> tag. Language placeholders will be resolved if the map result values are of the String type. Supported languages are simple, constant and groovy.

Use the following syntax to enforce use of languages:

$simple{...}, e.g. $simple{header.salesforceObjectType}
$constant{...}, e.g. $constant{Customer}
$groovy{...}, e.g. $groovy{exchange.in.headers.salesforceObjectType}

Example

Focus on:

Using filter configuration with parameters
URI filter

Configuration

<filter>
    <name>test-uri-filter-properties</name>
    <type>uri</type>
    <transformer>
        <language>groovy</language>
        <script>
            [q: 'select ' + headers['filter-resultFields']?.join(',') + ' from $simple{header.salesforceObjectType} and $groovy{exchange.in.headers.salesforceObjectType2} and $constant{Customer} where 1=1 and ' + headers['filter-condition']?.collect{it -> it.criteria[0].fieldName + it.criteria[0].operator.sign + it.criteria[0].value}.join(' and ')]
        </script>
    </transformer>
</filter>

Filter

new Filter(
        resultFields: "id,name,surname",
        sortBy: 'id',
        condition: new AndCondition(
                criteria: [new Restriction("id", Operator.lessThan, 10)]
        ),
        transformerRef: 'test-uri-filter-properties'
)

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