Example #10: Creating a resource file for use with Internet Explorer

All the previous examples in this documentation are rather contrived examples that seek to focus on one or more related aspects of the functionality in the PJResFile unit. This example is the first of three examples that aim to present useful code that uses several of the methods covered by other examples.

We will create a routine that takes a list of HTML and related files and creates a resource file which has a unique RT_HTML resource for each file. The resource contains the contents of the related file.

Such resources can be used for display in Internet Explorer, using the res:// protocol. See the article “How to create and use HTML resource files” for more information on this subject.

Here is the code of the routine:

procedure BuildHTMLResFile(const Files: TStrings; const ResFileName: string);
var
  ResFile: TPJResourceFile; // res file object
  Entry: TPJResourceEntry;  // a resource entry
  ResName: string;          // a resource name
  SrcFileName: string;      // a source file name
  SrcStm: TFileStream;      // source file stream
  FileIdx: Integer;         // loops thru Files
const
  LanguageID: Word = $0809; // UK English
begin
  ResFile := TPJResourceFile.Create;
  try
    // Loop through all source files
    for FileIdx := 0 to Pred(Files.Count) do
    begin
      // Record name of current file 0 should be fully specified
      SrcFileName := Files[FileIdx];
      // Construct resource name from source file name, without path. If the
      // resource name already exists repeatedly prepend underscores until a
      // unique name is found
      ResName := ExtractFileName(SrcFileName);
      while ResFile.EntryExists(RT_HTML, PChar(ResName), LanguageID) do
        ResName := '_' + ResName;
      // Create new resource for current file - this will be unique
      Entry := ResFile.AddEntry(RT_HTML, PChar(ResName), LanguageID);
      // Copy source file into resource data
      SrcStm := TFileStream.Create(SrcFileName, fmOpenRead);
      try
        Entry.Data.CopyFrom(SrcStm, 0);
        Entry.Data.Position := 0;
      finally
        SrcStm.Free;
      end;
    end;
    // Save resource file
    ResFile.SaveToFile(ResFileName);
  finally
    ResFile.Free; // this also frees resource entry objects
  end;
end;

The Files parameter of the routine is a string list containing the (fully specified) names of files that are to be included in the resource file. The ResFileName parameter receives the name of the output file which will be a valid 32 bit resource file.

The comments in the code should explain what is happening.

Alternative Approach [~>1.1]

The above code can be simplified when using v1.1 of the Resource File Unit because of its new LoadDataFromFile [~>1.1] method. Using this method we can replace all the stream processing code between the // Copy source file into resource data comment and the end of the loop with a single line of code:

      ...
      // 5: Copy source file into resource data
      SrcStm := TFileStream.Create(SrcFileName, fmOpenRead);
      Entry.LoadDataFromFile(SrcFileName, False);
    end;
    ...

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Example #10: Creating a resource file for use with Internet Explorer