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User Guide Overview

Apache Axis2/C is a web services framework that supports both modern HTTP/2 JSON-RPC and legacy SOAP protocols.

Core Concepts

Services

A service is a deployable unit that exposes one or more operations. Services are packaged as shared libraries (.so on Linux, .dll on Windows) with a services.xml descriptor.

services/
└── MyService/
    ├── libmyservice.so
    └── services.xml

Operations

An operation is a callable method within a service. Each operation has:

  • A name (used in the URL path or SOAP action)
  • A message receiver (JSON or SOAP)
  • Optional handlers for pre/post processing

Message Context

The message context carries request/response data through the processing pipeline:

  • HTTP headers
  • Protocol information (HTTP/2 vs HTTP/1.1)
  • Client certificates (for mTLS)
  • Service and operation references

Architecture

Processing Pipeline

Request → Transport → Handlers → Service → Handlers → Transport → Response
  1. Transport Layer: HTTP/2 (nghttp2) or HTTP/1.1
  2. In Handlers: Authentication, logging, validation
  3. Service Invocation: Your business logic
  4. Out Handlers: Response transformation
  5. Transport Layer: Send response

Module System

Axis2/C uses a module system for extensibility:

  • Rampart - WS-Security (legacy SOAP)
  • mod_axis2 - Apache httpd integration

Configuration Files

axis2.xml

Main server configuration:

  • Transport settings (HTTP/2, TLS)
  • Module references
  • Global handlers
  • Service deployment paths

See axis2.xml Configuration.

services.xml

Per-service configuration:

  • Service description
  • Operations
  • Parameters
  • Handlers

See Services Guide.

Protocol Support

Modern protocol stack for new applications:

  • Binary framing, multiplexing
  • JSON request/response bodies
  • TLS 1.3 with mTLS support

See the HTTP/2 + JSON User Guide for detailed examples and configuration.

Legacy SOAP/HTTP

For existing SOAP integrations:

  • SOAP 1.1 and 1.2
  • WS-* specifications
  • WSDL support

Next Steps

Support the ASF