Configuration

You can customize the behavior of the comparison checks using OpenAPI extensions.

The extensions follow the format: x-opc-config-${extension}, where the extension matches one of the items below. To be recognized by PactFlow On-Premises, you must add the extension to the info section of your OpenAPI Specification (OAS). For example, to customize the Base URL for comparisons, add the following:

openapi: 3.1.0
info:  
    x-opc-config-base-path: /custom-prefix  
    title: OAS  
    version: 1.0.0

paths:  
    /path:    
        get:      
            responses:        
                "200":          
                    description: ok

This results in checks matching the path /custom-prefix/path, rather than simply /path.

Configuration Options

With the introduction of a new comparison engine (April 2025), we added additional capabilities to PactFlow.

Some of the changes are not backward compatible with the previous engine and are disabled by default to prevent unexpected build failures. The table below describes the options available.

Categories of options

  • Compatibility mode. Items labeled "compatibility mode" indicate a new (and likely, improved) behavior is suppressed to ensure it remains consistent with the previous behavior.

  • Bugs. Items labeled "bug" indicate a bug in the previous engine - these are almost certainly suppressing a genuine issue and should be disabled as soon as possible.

  • Behavior. Items labeled "behavior" indicate a preference for how the tool should behave under certain conditions.

Options

Option

Default Value

Description

Example

x-opc-config-cast-objects-in-pact

true

Bug. The previous engine interpreted the literal string "[object Object]" in request query strings as empty objects ({}). This indicates an issue with an invalid pact file.

N/A

x-opc-config-disable-multipart-formdata

true

Compatibility mode. Disables validation of multipart forms. Setting this to true ignores all multipart request/response bodies during in validation.

N/A

x-opc-config-ignore-duplicate-slashes

true

Compatibility mode. Duplicate slashes (for example, // or ///) are treated as a single slash.

// will be treated as / if enabled.

x-opc-config-ignore-trailing-slash

true

Compatibility mode. Trailing slashes.

/foo and /foo/ will be considered the same if enabled.

x-opc-config-legacy-parser

true

Compatibility mode. Supports nested query string objects and key/value pairs in x-www-form-urlencoded bodies for more complicated schemas.

a.b=c is parsed as { "a.b": "c" } in compatibility mode, otherwise { "a" : { "b": "c: } } and a[b]=c is parsed as { "a[b]": "c" } in compatibility mode, otherwise { "a" : { "b": "c: } } OPC and a=1,2 is parsed as { "a": "1,2" } in compatibility mode, otherwise { "a": ["1", "2"] }.

x-opc-config-no-authorization-schema

true

Compatibility mode. Disables validation against schema.

Authorization: Bearer !@#$%^& or Authorization: Basic abc will pass if enabled.

x-opc-config-no-percent-encoding

true

Compatibility mode. Allows percentages in path, even if it is not percent encoded.

N/A

x-opc-config-no-transform-non-nullable-response-schema

true

Bug. The previous engine had a bug whereby nullable response schemas were not transformed correctly.

N/A

x-opc-config-no-validate-complex-parameters

true

Compatibility mode.

Given the header Some-JSON-Header: "foo=bar&baz=bat...", the value will be deserialised into an object with properties foo and baz to be compared to the schema.

x-opc-config-no-validate-request-body-unless-application-json

true

Bug. The previous engine ignored body matching if the schema didn't include application/json in the list of supported request content types.

N/A

x-opc-config-base-path

undefined

Behavior. In OAS 3 and 2, all API endpoints are considered to be relative to the base URL. For example, assuming the base URL of https://api.example.com/v1, the /users endpoint refers to https://api.example.com/v1/users. As the base URL may be specified as an array, and in multiple nested levels within the document, there is no reliable way to determine the correct URL. This item allows you to specify the value for the purposes of validation.

/custom-prefix

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