Use PHP & XML to compile a mini search engine (3)

Source: Internet
Author: User
4. a subtree is displayed on the basis of the procedures in chapter 3. I will not comment out the code in the second chapter. The following code is the basis of our mini search engine. on the basis of chapter 3 program, we can display a subtree.

I will not comment out the code in the second chapter.

The following code is the basis of our mini search engine.

Because it is necessary to display the information of a word category (such as program design-> PHP->.

We locate the element based on the number of layers of the element and the number of the layer on which it is located.

For example:



Links (0, 1)

+ ---- Web (1, 1)

+ ---- Sub (1, 2)

| + ---- Web (2, 1)

| + ---- Sub (2, 2)

| + ---- Web (3, 1)

| + ---- Sub (3, 2)



:

:

:



__________________________________________________________










// XML file

$ File = "demo. xml ";







// Functions used to parse XML files

Function xml_parse_from_file ($ parser, $ file)

{

If (! File_exists ($ file ))

{

Die ("Can't find file" $ file ".");

}



If (! ($ Fp = @ fopen ($ file, "r ")))

{

Die ("Can't open file" $ file ".");

}



While ($ data = fread ($ fp, 4096 ))

{

If (! Xml_parse ($ parser, $ data, feof ($ fp )))

{

Return (false );

}

}



Fclose ($ fp );



Return (true );

}







Function start_element ($ parser, $ name, $ attrs)

{

Global $ level, $ levelcount, $ maxlevel, $ hide, $ lev, $ num, $ PHP_SELF;



$ Level + = 1;

If ($ level> $ maxlevel) $ maxlevel = $ level;

$ Levelcount [$ level] + = 1;



If ($ hide) {// Determine whether the sub-tree is in the range of $ hide = FALSE

If ($ level = $ lev& & $ levelcount [$ level] = $ num) $ hide = FALSE;

} Else {

If ($ level <= $ lev) $ hide = TRUE;

}





If (! $ Hide ){

Echo"

";

For ($ I = 1; $ I <= ($ level-1-$ EV); $ I ++) echo "| ";

If ($ level-$ lev> 0) echo "+ ----";



Echo "".

// Add the join of each element node

Trim ($ name )."";



While (list ($ key, $ val) = each ($ attrs )){

Echo "$ key => $ val ;";

}

}





}



Function stop_element ($ parser, $ name)

{

Global $ level;



$ Level-= 1;

}



Function data ($ parser, $ data)

{

Global $ level, $ hide;

If (! $ Hide)

If (trim ($ data )! = ""){

Echo trim ($ data );

}

}





// Main start

Global $ hide, $ lev, $ num, $ PHP_SELF;

$ Level =-1;

$ Hide = TRUE;



Echo"

Root

";



If ($ lev= = "") {$ lev= 0; $ num = 1 ;}



$ Parser = xml_parser_create ();



Xml_set_element_handler ($ parser, "start_element", "stop_element ");

Xml_set_character_data_handler ($ parser, "data ");

Xml_parser_set_option ($ parser, XML_OPTION_CASE_FOLDING, 0 );



$ Ret = xml_parse_from_file ($ parser, $ file );

If (! $ Ret)

{

Die (sprintf ("XML error: % s at line % d ",

Xml_error_string (xml_get_error_code ($ parser )),

Xml_get_current_line_number ($ parser )));

}



Xml_parser_free ($ parser );





?>



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