openapi2wadl.py : OpenAPI to XSD+WADL+WSDL

Python script to converts JSON OpenAPI 3.0 (or Swagger 2.0) into WADL, WSDL and XSD files.
Supports a wide set of constructs and preserves detailed data types in the generated XSD schema.

---

🚀 Features

✅ WADL Generation

• Supports both Swagger 2.0 and OpenAPI 3.0 (auto-detected)
• Generates WADL <resources>, <resource>, <method>, <request>, and <response>
• Supports produces / consumes in Swagger and content in OpenAPI
• Includes all declared media types in <representation>
• Handles parameters of type query, header, path, and body
• Resolves all $ref references for requests and responses

✅ XSD Schema Generation

• Generates a comprehensive XML Schema (XSD).
• Nested arrays and objects are fully managed.
• Nested $ref schema chains are fully resolved.
• Directly maps required property to minOccurs="0" XSD attribute when necessary.
• Support the following restriction tokens :
  • minLength, maxLength, pattern, minimum, maximum, exclusiveMinimum, exclusiveMaximum.
• Supports nullability in two different ways:
  • Directly maps nullable property to the nillable XSD attribute.
  • Replace not-nullable atomic types with reusable union simpleType that allow empty string as a surrogate for the null value (for those frameworks that do not support the nillable attribute).
• Consolidates recurring string length restrictions into reusable simpleType's named and ordered according to length range (e.g. string64, string10to20, string32Nillable) to improve readability and simplify detection of inappropriate or incomplete type definitions.
• Improve human readability:
  • Custom pretty print.
  • Only types referenced in WADL are declared as global elements.
  • Aligns and indents type attributes for readability (padding applied).
  • Organizes schema in separated block Special Types, Simple Types, Complex Types, Elements.

Supported Types & Formats

The following Open API Types & Format modifiers are currently supported:

Type	Format	Mapped XSD Type	Notes
boolean	-	xs:boolean	true / false
integer	-	xs:integer	Generic integer number
integer	int32	xs:int	32 bit (-2³¹ to 2³¹-1)
integer	int64	xs:long	64 bit (-2⁶³ to 2⁶³-1)
number	-	xs:decimal	Arbitrary precision decimal
number	float	xs:float	32 bit floating point
number	double	xs:double	64 bit floating point
string	-	xs:string	Generic text
string	byte	xs:base64Binary	Binary encoded string
string	date	xs:date	Short date (YYYY-MM-DD)
string	date-time	xs:dateTime	Date & Time format ISO 8601

---

🚫 Limitations

• Unsupported numeric constraint: multipleOf
• Composition constructs (allOf, anyOf, oneOf) are not yet supported
• Schema description / title annotations are not included in converted files

---

🛠️ Usage

python openapi2wadl.py <input_file.json> [--output-dir <output_directory>]

• The output directory is optional; if not provided, files are saved in the current directory
• Output files are named after the input JSON file:
  • <input_file>.xsd
  • <input_file>.wadl
  • <input_file>.wsdl

---

📌 Recommendations

• Use $ref for reusable components (under definitions or components.schemas)
• Provide clear produces and consumes values or content entries for media type mapping
• Avoid unsupported constraints like multipleOf