{
* Web.UExceptions.pas
*
* Provides exception classes used by web services classes and code.
*
* $Rev$
* $Date$
*
* ***** BEGIN LICENSE BLOCK *****
*
* Version: MPL 1.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The Original Code is Web.UExceptions.pas, formerly
* NsWebServices.UExceptions.pas.
*
* The Initial Developer of the Original Code is Peter Johnson
* (http://www.delphidabbler.com/).
*
* Portions created by the Initial Developer are Copyright (C) 2010 Peter
* Johnson. All Rights Reserved.
*
* Contributor(s)
* NONE
*
* ***** END LICENSE BLOCK *****
}
unit Web.UExceptions;
interface
uses
// Delphi
SysUtils,
// Indy
IdHTTP,
// Project
UExceptions;
type
{
EWebError:
Base class for exceptions raised by any code that accesses the web.
}
EWebError = class(ECodeSnip);
{
EHTTPError:
Exception raised when web server HTTP error is detected.
}
EHTTPError = class(EWebError)
strict private
fHTTPErrorCode: Integer; // HTTPErrorCode property value
public
constructor Create(const E: EIdHTTPProtocolException); overload;
{Constructor. Creates object from properties of given exception.
@param E [in] Instance of exception from which to create this exception.
E.ReplyErrorCode is stored in HTTPErrorCode property and E.Message is
stored in Message property.
}
procedure Assign(const E: Exception); override;
{Assigns properties of another exception to this one.
@param E [in] Exception whose properties are to be copied. Must be an
EHTTPError or an EIdHTTPProtocolException instance.
}
property HTTPErrorCode: Integer read fHTTPErrorCode;
{HTTP error code from web server}
end;
{
EWebTransmissionError:
Type of exception raised when an error in transmission over the net is
detected.
}
EWebTransmissionError = class(EWebError);
{
EWebConnectionError:
Exception raised when there is a problem connecting to web server (i.e.
socket error).
}
EWebConnectionError = class(EWebError);
{
EWebService:
Base class for all errors generated by web services. None of these
exceptions are treated as bugs.
}
EWebService = class(EWebError);
{
EWebServiceFailure:
Exception raised when the web service fails to response as expected.
}
EWebServiceFailure = class(EWebService);
{
EWebServiceError:
Exception raised when a web service returns an error condition as a response
to a command. It has a non-zero error code in addition to the error message.
}
EWebServiceError = class(EWebService)
strict private
fErrorCode: Integer; // Value of ErrorCode property
public
constructor Create(const Msg: string; const ErrorCode: Integer = -1);
overload;
{Constructor. Constructs exception object with an error code in addition
to standard error message.
@param Message [in] Error message.
@param ErrorCode [in] Optional non-zero error code (defaults to -1).
}
constructor CreateFmt(const Fmt: string; const Args: array of const;
const ErrorCode: Integer = -1); overload;
{Constructor. Constructs exception object with an error code in addition
to message built from format string and arguments.
@param Fmt [in] Format for message string.
@param Args [in] Arguments to be included in formatted message string.
@param ErrorCode [in] Optional non-zero error code (defaults to -1).
}
procedure Assign(const E: Exception); override;
{Assigns properties of another exception to this one.
@param E [in] Exception whose properties are to be copied. Must be an
EWebServiceError instance.
}
property ErrorCode: Integer read fErrorCode;
{Non-zero error code}
end;
implementation
{ EHTTPError }
procedure EHTTPError.Assign(const E: Exception);
{Assigns properties of another exception to this one.
@param E [in] Exception whose properties are to be copied. Must be an
EHTTPError or an EIdHTTPProtocolException instance.
}
begin
Assert((E is EHTTPError) or (E is EIdHTTPProtocolException),
ClassName + '.Assign: E must be EHTTPError or EIdHTTPProtocolException');
inherited;
if E is EHTTPError then
fHTTPErrorCode := (E as EHTTPError).fHTTPErrorCode
else
fHTTPErrorCode := (E as EIdHTTPProtocolException).ErrorCode;
end;
constructor EHTTPError.Create(const E: EIdHTTPProtocolException);
{Constructor. Creates object from properties of given exception.
@param E [in] Instance of exception from which to create this exception.
E.ReplyErrorCode is stored in HTTPErrorCode property and E.Message is
stored in Message property.
}
begin
inherited Create(E.Message);
fHTTPErrorCode := E.ErrorCode;
end;
{ EWebServiceError }
procedure EWebServiceError.Assign(const E: Exception);
{Assigns properties of another exception to this one.
@param E [in] Exception whose properties are to be copied. Must be an
EWebServiceError instance.
}
begin
Assert(E is EWebServiceError,
ClassName + '.Assign: E must be EWebServiceError');
inherited;
fErrorCode := (E as EWebServiceError).fErrorCode;
end;
constructor EWebServiceError.Create(const Msg: string;
const ErrorCode: Integer);
{Constructor. Constructs exception object with an error code in addition
to standard error message.
@param Message [in] Error message.
@param ErrorCode [in] Optional non-zero error code (defaults to -1).
}
begin
Assert(ErrorCode <> 0, ClassName + '.Create: zero error code');
inherited Create(Msg);
fErrorCode := ErrorCode;
end;
constructor EWebServiceError.CreateFmt(const Fmt: string;
const Args: array of const; const ErrorCode: Integer);
{Constructor. Constructs exception object with an error code in addition to
message built from format string and arguments.
@param Fmt [in] Format for message string.
@param Args [in] Arguments to be included in formatted message string.
@param ErrorCode [in] Optional non-zero error code (defaults to -1).
}
begin
Assert(ErrorCode <> 0, ClassName + '.CreateFmt: zero error code');
Create(Format(Fmt, Args), ErrorCode);
end;
end.
