用于解析ERB文件的库 [英] Library to parse ERB files

问题描述

我试图以Hpricot/Nokogiri类型的方式解析而不是评估Rails ERB文件.我尝试解析的文件包含HTML片段，这些片段与使用ERB(标准rails视图文件)生成的动态内容混合在一起，我正在寻找一个不仅可以解析周围内容的库，而且可以像Hpricot或Nokogiri一样处理， ERB符号，<％，<％=等，就好像它们是html/xml标签一样.

I am attempting to parse, not evaluate, rails ERB files in a Hpricot/Nokogiri type manner. The files I am attempting to parse contain HTML fragments intermixed with dynamic content generated using ERB (standard rails view files) I am looking for a library that will not only parse the surrounding content, much the way that Hpricot or Nokogiri will but will also treat the ERB symbols, <%, <%= etc, as though they were html/xml tags.

理想情况下，我会得到类似DOM的结构，其中<％，<％=等符号将被包含为它们自己的节点类型.

Ideally I would get back a DOM like structure where the <%, <%= etc symbols would be included as their own node types.

我知道可以使用正则表达式将某些内容合并在一起，但是我在寻找一种更可靠的方法，因为我正在开发一种工具，该工具需要在非常大的视图代码库中运行，其中html内容和erb内容很重要.

I know that it is possible to hack something together using regular expressions but I was looking for something a bit more reliable as I am developing a tool that I need to run on a very large view code base where both the html content and the erb content are important.

例如，诸如以下内容:

blah blah blah
<div>My Great Text <%= my_dynamic_expression %></div>

将返回一个像这样的树结构:

Would return a tree structure like:

root
 - text_node (blah blah blah)
 - element (div)
    - text_node (My Great Text )
        - erb_node (<%=)

推荐答案

我最终通过使用RLex，

I eventually ended up solving this problem by using RLex, http://raa.ruby-lang.org/project/ruby-lex/, the ruby version of lex with the following grammer:

%{

#define NUM 257

#define OPTOK 258
#define IDENT 259
#define OPETOK 260
#define CLSTOK 261
#define CLTOK 262
#define FLOAT 263
#define FIXNUM 264
#define WORD 265
#define STRING_DOUBLE_QUOTE 266
#define STRING_SINGLE_QUOTE 267

#define TAG_START 268
#define TAG_END 269
#define TAG_SELF_CONTAINED 270
#define ERB_BLOCK_START 271
#define ERB_BLOCK_END 272
#define ERB_STRING_START 273
#define ERB_STRING_END 274
#define TAG_NO_TEXT_START 275
#define TAG_NO_TEXT_END 276
#define WHITE_SPACE 277
%}

digit   [0-9]
blank   [ ]
letter  [A-Za-z]
name1   [A-Za-z_]
name2   [A-Za-z_0-9]
valid_tag_character [A-Za-z0-9"'=@_():/ ] 
ignore_tags style|script
%%

{blank}+"\n"                  { return [ WHITE_SPACE, yytext ] } 
"\n"{blank}+                  { return [ WHITE_SPACE, yytext ] } 
{blank}+"\n"{blank}+                  { return [ WHITE_SPACE, yytext ] } 

"\r"                  { return [ WHITE_SPACE, yytext ] } 
"\n"            { return[ yytext[0], yytext[0..0] ] };
"\t"            { return[ yytext[0], yytext[0..0] ] };

^{blank}+       { return [ WHITE_SPACE, yytext ] }

{blank}+$       { return [ WHITE_SPACE, yytext ] };

""   { return [ TAG_NO_TEXT_START, yytext ] }
""  { return [ TAG_NO_TEXT_END, yytext ] }
""                   { return [ TAG_SELF_CONTAINED, yytext ] }
""  { return [ TAG_SELF_CONTAINED, yytext ] }
""    { return [ TAG_START, yytext ] }
""   { return [ TAG_END, yytext ] }

""  { return [ ERB_BLOCK_END, yytext ] }
""  { return [ ERB_STRING_END, yytext ] }


{letter}+       { return [ WORD, yytext ] }


\".*\"          { return [ STRING_DOUBLE_QUOTE, yytext ] }
'.*'                    { return [ STRING_SINGLE_QUOTE, yytext ] }
.           { return [ yytext[0], yytext[0..0] ] }

%%

这不是一个完整的语法，但出于我的目的，找到并重新发送文本可以正常工作.我将语法与这小段代码结合在一起:

This is not a complete grammer but for my purposes, locating and re-emitting text, it worked. I combined that grammer with this small piece of code:

    text_handler = MakeYourOwnCallbackHandler.new

    l = Erblex.new
    l.yyin = File.open(file_name, "r")

    loop do
      a,v = l.yylex
      break if a == 0

      if( a < WORD )
        text_handler.character( v.to_s, a )
      else
        case a
        when WORD
          text_handler.text( v.to_s )
        when TAG_START
          text_handler.start_tag( v.to_s )
        when TAG_END
          text_handler.end_tag( v.to_s )
        when WHITESPACE
          text_handler.white_space( v.to_s )
        when ERB_BLOCK_START
          text_handler.erb_block_start( v.to_s )
        when ERB_BLOCK_END
          text_handler.erb_block_end( v.to_s )      
        when ERB_STRING_START
          text_handler.erb_string_start( v.to_s )
        when ERB_STRING_END
          self.text_handler.erb_string_end( v.to_s )
        when TAG_NO_TEXT_START
          text_handler.ignorable_tag_start( v.to_s )
        when TAG_NO_TEXT_END
          text_handler.ignorable_tag_end( v.to_s )
        when STRING_DOUBLE_QUOTE
          text_handler.string_double_quote( v.to_s )
        when STRING_SINGLE_QUOTE
          text_handler.string_single_quote( v.to_s )
        when TAG_SELF_CONTAINED
          text_handler.tag_self_contained( v.to_s )
        end
      end  
    end

这篇关于用于解析ERB文件的库的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！