================================================================================

Documentation of classes that access web-services on behalf of CodeSnip.

================================================================================


DelphiDabbler Standard Web Service
--------------------------------------------------------------------------------

A DelphiDabbler Standard Web Service object has the following attributes:

It provides the correct user agent string. Web services return HTTP error 403 if
the user agent is not as expected. User agents can also specify the version of
the web service to be used.

It submits data to the using HTTP Post.

Information is POSTed to the web service either in the form of URL encoded query
strings or as raw post data. Which format is used depends on web service.

Web services respond with text data. The text is encoded as the default for the
server which is taken to be ISO-8859-1 (Latin 1).

The response text is split into lines by CRLF pairs. There is always at least
one line. Any trailing CRLFs should be stripped from the text.

The first line always contains a status code. A zero code indicates success,
while non-zero codes indicate an error. The meaning of the error code is
specific to the web service. Consult the documentation for the service for
details.

A successful response usually, but not always includes further information
starting from the second line of the text. The meaning of this text depends on
the web service. Consult the documentation for the service for details.

An error response should include an error message starting from the second line
of the text. Error messages often take up just a single line, but may have more
than one line.

The response format, after trimming, in ABNF is:

  response = status_code CRLF data
  status_code = success_code / error_code
  success_code = "0"
  error_code = ["-"] 1*DIGIT
  data = data_line [CRLF data]
  data_line = 0*[VCHAR | WSP]

The class TDDabStdWebService provides core functionality for working with
standard web services. In particular it:

* Provides methods for posting data in the form of query strings to the web
  service.

* Handles the response, checking the status code. When an error code is received
  an exception is raised using the error message from the response. In the case
  of a successful response the status code line is stripped and the remaining
  data made available for processing by descendant classes.


Class heirachy
--------------------------------------------------------------------------------

TBaseWebService
|
+-- TDDabStdWebService
    |
    +-- TCodeSubmitter
    |
    +-- TDownloadMgr
    |
    +-- TMailListSubscriber
    |
    +-- TRegistrar


--------------------------------------------------------------------------------
$Rev$
$Date$
--------------------------------------------------------------------------------