This parameter provides configurable control over the method used by the Web Gateway to notify clients of the amount of data contained in each response.
Web clients typically require some form of response size notification if HTTP KeepAlive connectivity is used. Under these circumstances, the Web Gateway defaults to using chunked transfer encoding, provided HTTP v1.1 is in use. If an earlier HTTP protocol is in force it buffers the response data received from InterSystems IRIS and generate a content-length header instead. Also, in cases where the entire response fits into one output buffer a content-length header is generated instead of using chunked transfer.
There are scenarios in which it is desirable to instruct the Web Gateway to specifically use one method or the other. For example, in cases where HTTP v1.1 is used but some intermediary (such as a proxy) is unable to properly support chunked transfer. Also, while not sending any form of size notification (such as, where the close connection event is used as the response terminator) should be supported by all web clients, it is nevertheless recommended as 'good practice' that all responses should be accompanied by some form of size notification. Indeed, some clients require this.
The following options are provided:
This parameter is supplemented with a check box to instruct the Web Gateway to always generate a size notification for all requests regardless of whether or not KeepAlive is used.
There is a 500 kilobyte limit on the size of HTTP responses that specify a content-length header, as opposed to chunked responses. If you exceed this limit, a warning message appears in the CSP log:
WARNING: Unable to generate a 'Content-Length' header directive for this oversize response (Current size: size; Maximum buffer size allowed: 500000)