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libPasMyHTML

It is delphi and object pascal bindings and wrapper around MyHTML library. MyHTML is a fast HTML 5 Parser using Threads.

Table of contents

Requirements

Library is tested for

  • Embarcadero (R) Delphi 10.3 on Windows 7 Service Pack 1 (Version 6.1, Build 7601, 64-bit Edition)
  • FreePascal Compiler (3.2.0) and Lazarus IDE (2.0.10) on Ubuntu Linux 5.8.0-33-generic x86_64

Installation

Get the sources and add the source directory to the project search path. For FPC add the source directory to the fpc.cfg file.

Usage

Clone the repository git clone https://github.com/isemenkov/libpasmyhtml.

Add the unit you want to use to the uses clause.

Testing

A testing framework consists of the following ingredients:

  1. Test runner project located in unit-tests directory.
  2. Test cases (DUnit for Delphi and FPCUnit for FPC based) for all containers classes.

Bindings

libpasmyhtml.pas file contains the MyHTML translated headers to use this library in pascal programs.

Usage example

  uses
    libpasmyhtml, utils.api.cstring;

  const
    HTMLDocument = '<!DOCTYPE html>'                              + sLineBreak +
    '<html>'                                                      + sLineBreak +
    '<head>'                                                      + sLineBreak +
      '<meta charset="utf-8" />'                                  + sLineBreak +
      '<!--[if lt IE 9]><script src="https://cdnjs.cloudflare.com'+
      '/ajax/libs/html5shiv/3.7.3/html5shiv.min.js"></script>'    +
      '<![endif]-->'                                              + sLineBreak +
      '<title>Document Title</title>'                             + sLineBreak +
      '<meta name="keywords" content="some_keywords keywords" />' + sLineBreak +
      '<meta name="description" content="description" />'         + sLineBreak +
      '<link href="style.css" rel="stylesheet">'                  + sLineBreak +
    '</head>'                                                     + sLineBreak +
    '<body>'                                                      + sLineBreak +
    '</body>'                                                     + sLineBreak +
    '</html>';

  var
    Node : pmyhtml_tree_node_t;
    Title : string;
    Error : mystatus_t;
    HTML : pmyhtml_t;
    Tree : pmyhtml_tree_t;
    Encoding : myencoding_t;

  function FindNextNodeById (ANode : pmyhtml_tree_node_t; AId : myhtml_tags_t) : pmyhtml_tree_node_t; 
    inline;
  begin
    while (ANode <> nil) and (myhtml_node_tag_id(ANode) <> myhtml_tag_id_t(AId)) do
    begin
      ANode := myhtml_node_next(ANode);
    end;
    Result := ANode;
  end;

  function NodeTextValue (ANode : pmyhtml_tree_node_t) : string; inline;
  var
    TextNode : pmyhtml_tree_node_t;
  begin
    if ANode <> nil then
      TextNode := myhtml_node_child(ANode);
      if (TextNode <> nil) and (myhtml_tags_t(myhtml_node_tag_t(TextNode)) = MyHTML_TAG__TEXT) then
      begin
        Result := API.CString.Create(myhtml_node_text(TextNode, nil)).ToString;
      end else
        Result := '';
    end else
      Result := '';
  end;

  begin
    HTML := myhtml_create;
    myhtml_init(HTML, MyHTML_OPTIONS_PARSE_MODE_SEPARATELY, 1, 4096);
    Tree := myhtml_tree_create;
    myhtml_tree_init(Tree, HTML);
    myhtml_tree_parse_flags_set(Tree, MyHTML_TREE_PARSE_FLAGS_CLEAN);

    Error := myhtml_parse(Tree, MyENCODING_UTF_8, 
      API.CString.Create(HTMLDocument).ToPAnsiChar, Length(HTMLDocument));
    if Error = mystatus_t(MyHTML_STATUS_OK) then
    begin
      Node := myhtml_tree_get_node_head(Tree);
      if Node <> nil then
      begin
        Node := myhtml_node_child(Node);
        if Node <> nil then
        begin
          Node := FindNextNodeById(Node, MyHTML_TAG_TITLE);
          if Node <> nil then
          begin
            Title := NodeTextValue(Node);
          end;
        end;
      end;
    end;
    
    myhtml_tree_clean(Tree);
    myhtml_clean(HTML);
    myhtml_tree_destroy(Tree);
    myhtml_destroy(HTML);
  end;

Object wrapper

pasmyhtml.pas file contains the MyHTML object wrapper.

Usage example

  uses
    pasmyhtml;

  const
    HTMLDocument = '<!DOCTYPE html>'                              + sLineBreak +
    '<html>'                                                      + sLineBreak +
    '<head>'                                                      + sLineBreak +
      '<meta charset="utf-8" />'                                  + sLineBreak +
      '<!--[if lt IE 9]><script src="https://cdnjs.cloudflare.com'+
      '/ajax/libs/html5shiv/3.7.3/html5shiv.min.js"></script>'    +
      '<![endif]-->'                                              + sLineBreak +
      '<title>Document Title</title>'                             + sLineBreak +
      '<meta name="keywords" content="some_keywords keywords" />' + sLineBreak +
      '<meta name="description" content="description" />'         + sLineBreak +
      '<link href="style.css" rel="stylesheet">'                  + sLineBreak +
    '</head>'                                                     + sLineBreak +
    '<body>'                                                      + sLineBreak +
    '</body>'                                                     + sLineBreak +
    '</html>';

  var
    Parser : TParser;
    Node : TParser.TTagNode;
    Value : string;

  begin
    Parser := TParser.Create(MyHTML_OPTIONS_PARSE_MODE_SEPARATELY, MyENCODE_UTF_8, 1, 4096,
      MyHTML_TREE_PARSE_FLAGS_CLEAN);
    Node := Parser.Parse(HTMLDocument, DOCUMENT_HEAD);
    Node := Node.FirstChildrenNode(TParser.TFilter.Create.Tag(MyHTML_TAG_TITLE));
    if Node.IsOk then
    begin
      Value := Node.Value;
    end;
  end;