Configuring the Plain HTTP Receiver Adapter

Use

The plain HTTP outbound channel is a service provided by the Integration Engine. The system is addressed when technical routing determines a corresponding communication channel for the logical receiver from logical routing. The system sends the payload of the message to an HTTP address using HTTP, without being enhanced with an envelope.

Procedure

The plain HTTP adapter gives the receiver system the following specifications:
- Transport Protocol: HTTP 1.0
- Message Protocol: XI payload in HTTP body
- Adapter Engine: Integration Server

Define the Addressing Type

Select the Addressing Type:
- URL Address
  - Specify the target host, service number, and path prefix including query string:
    http://<hostname:port>/<path>?<query-string>
    
    You can identify the target host (HTTP port) of a SAP Web Application Server by using the ICM monitor.
    
    More information: ICM Monitor
  - You can specify the HTTP Proxy Host and HTTP Proxy Port.
    This is useful if there is a firewall between the plain HTTP adapter and the receiver system.
  Authentication data for the receiver system, more information: Transaction Display and Maintain RFC Destinations (SM59).
- HTTP Destination
  Specify the HTTP Destination.
- Under Content Type, specify the format that the content (the payload) is to have.
Enter optional header fields for the receiver-specific protocol in the table.
Select Additional Query String Attributes:
- Sender Party
- Sender Service
- Receiver Interface
- Message ID
- Quality of Service
  More information: Quality of Service
- Queue ID (required if Quality of Service is EOIO)

Define XI Payload Manipulation

Under XML Code, specify the character set of the payload.
If you want special characters that could be interpreted as control characters to be replaced with escape characters (masked), select Mask Special Characters (URL Escaping).
This presents the XML in a URL-enabled format.
To enhance the payload for particular servers, enter the Prolog and Epilog.
Some external systems, for example, Web servers in marketplaces, can only process data if it is sent as an HTML form using HTTP.

A typical HTML form comprises named fields. When transferring a completed form to the server or a CGI program, the data must be transferred in such a way that the CGI script can recognize the fields that make up the form, and which data was entered in which field.

This is done with the aid of a prolog and an epilog.

The encoding method that separates the form fields and their data uses the following rules:
- Separate individual form elements, including their data, by using the ampersand (&).
- Separate the name and data of a form element by using an equals sign (=).
- Replace blanks in the entered data (for example, in multiple words) by using a plus sign (+).
- Rewrite all characters with the (enhanced) ASCII values 128 to 255 (hexadecimal 80 to FF) by using a hexadecimal character sequence, starting with a percentage sign (%) and followed by the hexadecimal value of the character.
  For example, the German umlaut ö is rewritten as %F6 in the ISO-8859-1 character set.
- All characters that occur in these rules as control characters (&, +, =, and %) are also rewritten hexadecimally in the same way as higher value ASCII characters.
More information below under Example.

Define Adapter-Specific Message Attributes

To evaluate adapter-specific attributes in the message header of the XI message, select Use Adapter-Specific Message Attributes.
If you want missing message attributes to trigger an error message, select Fail If Adapter-Specific Message Attributes Missing.
- If the indicator is set and the header for adapter-specific message attributes or one of the set attributes is missing from the message, this leads to a system error (red flag).
- If you do not set the indicator, and message attributes are missing, the adapter accesses information from the adapter configuration.
If you want to use an HTTP destination or URL set by the mapping, select URL or HTTP Destination.
The Addressing Type you selected above determines which indicator is displayed.

If you set the indicator, the URL or HTTP destination set dynamically is called by HTTP.

If the message header does not contain the URL or the HTTP destination, and you have set the Fail If Adapter-Specific Message Attributes Missing indicator, the XI message is set to status System Error. If you do not set the indicator, the URL or HTTP destination defined statically in the communication channel is used.

The technical names of the fields are:
- URL: TargetURL
- HTTP Destination: HTTPDest
If you want to use HTTP header fields, select Apply HTTP Header Fields and enter the fields in Field 1 to Field 6. The fields are embedded in the HTTP request under the names you enter here.
The technical names of the fields are HeaderFieldOne, .... HeaderFieldSix.
If you want to use URL parameters, select Use URL Parameters and enter the parameters in the fields Parameter 1 to Parameter 6. The parameters are included in the HTTP request under the names specified here.
The technical names of the fields are URLParamOne, …, URLParamSix.
If you want to save HTTP header fields from the synchronous response in the XI message header, choose HTTP Header Fields (Synchronous Response) and enter the fields in the fields Field 1 to Field 6.
The fields must have the same names as the fields that are also to be sent in the HTTP response.

The technical names of the fields are HeaderFieldOne,...,HeaderFieldSix.
- The attribute namespace for the adapter is: http://sap.com/xi/XI/System/HTTP.

Result

The entries you made above provide the technical information for the HTTP request.
The main payload of the message is sent as HTTP post to an HTTP address.
The HTTP body comprises the prolog, message payload, and epilog. The prolog and epilog are optional and enhance the payload for particular servers (for example, CGI servers). If the payload is to be sent as an HTML form using HTTP post, it is URL-escaped beforehand.

Example

Building the prolog and epilog: