LR实现普通文字转换为URL格式编码

http://motevich.blogspot.com/2007/09/loadrunner-convert-text-to-url-format.html

LoadRunner - how to convert a plain text to URLformat

The task - How to convert a plain text string to URL-format in LoadRunner?

Several days ago I faced with a simple task - it was needed to convert a passedparameter (which was in a plain text form) to URL-format. In other words, I hadto convert:

• string "ab"     to the same string "ab"
• string "a     b" to the string "a%20b"
• string "a     b_c%" to "a%20b%5Fc%25"
• and so on ...

The cause - Why it was needed?

LoadRunner script contained parameters, which should be passed to URL directly.Some my parameters contained special characters like spaces (" "),quotes ("), percentage ("%"), asterisks ("*") andothers. To be processed correctly by a browser and a web server, thesecharacters should be translated and passed as their hex-codes.

For example:

• a space character (" ") has hex-code     0x20, so it should be passed as "%20"
• underline character (" ") has hex-code     0x5F, so it should be passed as "%5F"

The ways on how to perform the task.

To perform this task I decided to use LoadRunner's web_convert_param function. Ididn't know at that time that this function does not satisfy my requirements.So, I was reluctant to write my own function EncodePlainToURL. Well, let'ssee both solutions.

1. web_convert_param function.
       
        As Help says, web_convert_param     function converts HTML to a URL or plain text.
        So, I wrote this code:

char sIn[] ="t es%d$ +eprst_";

lr_save_string(sIn,"InputParam");
web_convert_param("InputParam", "SourceEncoding=PLAIN",
           "TargetEncoding=URL", LAST);

lr_output_message("%s",lr_eval_string("{InputParam}"));

Press F5 toexecute the code, and.... H'm....
The input string "t es%d$ + eprst_" was converted to"t+es%25d%24+%2B+eprst_".
That means that space (" ") was converted to a plus("+"). I expected to see "%20" instead of a plus character.

Actually, it seems that "+" and "%20" are twins. Forexample Google uses a plus to encode a space within a search query. Forexample, if the query is "some text", then the URL will be:http://www.google.com/search?hl=en&q=some+text&btnG=Google+Search

I was tried to encode spaces (and others special characters) to theirhex-codes.
That's why the following function was written:

2. EncodePlainToURL function.
       
        The logic is simple enough:
   • If the current character is a digits or an      alphabetic letter, then pass it "as is"
   • Otherwise the current character is a special      one. So, hex-code should be written in this case

This is a codeof EncodePlainToURL function:

/*
 *   EncodePlainToURL converts aplain text string to an URL-form string.
 *
 *   Parameters: sIn  - input string to be encoded to URL format
 *               sOut - outputbuffer
 *     Note: the size of"sOut" parameter should be at least equal to triple size
 *           of "sIn"parameter plus one character(for end-terminator '\0')
 *
 *   Author: Dmitry Motevich
 *
 *   Examples: "a"           -> "a"
 *             "a b"         -> "a%20b"
 *             "ab_cc:\/c%" -> "a%20b%5Fcc%3A%2Fc%25"
 */
char*EncodePlainToURL(constchar*sIn,char*sOut)
{
    int i;
    char cCurChar;
    char sCurStr[4] = {0};

    sOut[0] ='\0';

    for(i =0;cCurChar = sIn[i];i++)
    {
        //if this is a digit or an alphabetic letter
        if(isdigit(cCurChar) || isalpha(cCurChar))
        {
            //then write the current character "as is"
            sprintf(sCurStr,"%c",cCurChar);
        }
        else
        {
            //else convert it to hex-form. "_" -> "%5F"
            sprintf(sCurStr,"%%%X",cCurChar);
        }

        //append current item to the output string
        strcat(sOut,sCurStr);
    }

    return sOut;
}

The example of usage is:

char sIn[] ="t es%d$ + eprst_";
char sOut[100];

lr_output_message("%s", EncodePlainToURL(sIn,sOut));

Execute thecode, and see the result:
The input string "t es%d$ + eprst_" was converted to"t%20es%25d%24%20%2B%20eprst%5F".

Yeah! :)
All special characters (including spaces) were converted to hex-code, i.e. toURL-format!