WEB HTTP Integration point: gateways, tunnels, and trunks

1. Gateways: Gateways can be used as a type of translator, abstracting a way to reach resources. A gateway is a binder between a resource and an application.
   • Like web proxies and gateways that convert between different versions of HTTP, they perform complex logic to communicate between endpoints. But because they are using the HTTP protocol on both sides, technically they are still proxies.
   • The gateway is described by a slash "/" to separate the server-side protocol from the client protocol. Example: HTTP/NNTP
   • Protocol Gateway:
     • Server-side Web Gateway (http/**): When a request flows into the original server, the server-side Web gateway translates the client HTTP request to another protocol.
     • Server-side Security Gateway (HTTP/HTTPS): An organization can encrypt all input Web requests through a gateway to provide additional privacy and security protection. HTTP is converted to HTTP on SSL via a secure gateway.
     • The Client Security Accelerator Gateway (HTTPS/HTTP), which is located in front of the Web server and is typically used as an invisible interception gateway or direction proxy. They accept secure HTTPS traffic, decrypt the secure traffic, and send normal HTTP requests to the Web server. HTTP requests on SSL are converted to HTTP requests on the protected internal LAN.
   • A resource gateway (application Server) that combines the target server and gateway in a single server.
   1. 1. The first popular Application Gateway API is the Universal Gateway Interface (Common Gateway interface,cgi). CGI is a standard set of interfaces that the Web server can use to load programs in response to HTTP requests for specific URLs;
      2. Fast CGI, which runs as a persistent daemon
      3. Server Extensions API
   • application interfaces and Web services
     • Web services can use XML to exchange information through SOAP. SOAP (Simple Object Access Protocol) is the standard way to add XML information to an HTTP message.
3. Tunneling (Web Tunnel): This way you can access applications that are not HTTP protocols through HTTP applications. The most common reason to use tunneling is to embed non-HTTP traffic in an HTTP connection so that traffic can pass through firewalls that allow only web traffic.
   • Use connect to create an HTTP tunnel.
5. Trunking (relay): is a simple HTTP proxy that does not fully comply with the HTTP specification. The relay is responsible for processing the portion of the connection that is established in HTTP, and then blind forwarding the bytes.
   • Trunking has a notorious disadvantage: the possibility of potentially suspending keep-alive connections. The relay receives the connection header, because it does not understand, so it will pass the word to the server without leaking. However, the connection is the first hop-on, only applicable to a single transmission link, should not be transmitted along the link down.

WEB HTTP Integration point: gateways, tunnels, and trunks