Difference between revisions of "User:LepreKhaun Resident/Workaround4Escaped Chars within JsonText"

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<lsl>//////////////////////////////
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<div><lsl>//////////////////////////////
 
// function string uList2Json (string type, list values)
 
// function string uList2Json (string type, list values)
 
// This function takes the exact same parameters as
 
// This function takes the exact same parameters as
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}
 
}
}</lsl>
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}</lsl></div>
  
 
Now, if I can just get the retrieval worked out as simply... ;=)
 
Now, if I can just get the retrieval worked out as simply... ;=)

Revision as of 16:29, 23 September 2013

uList2Json() and uJsonSetValue()

As many of you may be aware, LSL has the habit of "enhancing" Strings. This is regarded as a "feature" of the language and usually works out for the best, giving one the option of formatting chatted text by using "\t" and "\n". Unfortunately, one didn't have a way to opt out of this behavior. Put in computereze, LSL simply lacked "raw strings".

This has bedeviled those working with Json text, either for web communications or developing other uses for it, because some strings just wouldn't encode properly. That is to say, these are all perfectly valid Json strings that simply couldn't be directly formed with llList2Json() and llJsonSetValue():

  • "\"Go!\" he yelled.\n"
  • "She replied \"No!\""
  • "Copyright symbol is \u00A9"
  • "oops]"
  • "Control characters are \t\n\r\f\b"

I've spent a few weeks studying the problem, most of it going about it the wrong way, but had an epiphany. A one line addition Maestro Linden added to Json Usage in LSL on the 10th ("LSL strings which both begin and end with "\"" are interpreted literally as JSON strings, while those without are parsed when converted into JSON.") confirmed what I had begun to surmise- a Json String (being a LSL String that is further enclosed within double quotes) is a "raw string"! Once I had that in hand, the following two functions practically wrote themselves.


<lsl>//////////////////////////////

// function string uList2Json (string type, list values) // This function takes the exact same parameters as // llList2Json() but correctly encodes all possible strings // including those with escape characters within them. // // Initial strings must escape all instances of the // desired escape character itself // (ie "\\t" => '\t', "\\\\" => '\\', "\\/" => '\/') // as well as any double quotes ("\\\"" => '\"') // // Version 1.0 by LepreKhaun 9/19/2013 // May be freely used, modified and distributed with this header intact. /////////////////////////////// string uList2Json (string type, list values) {

integer iter = -1; integer listLength = llGetListLength(values);

// Step through list, hitting every other item if JSON_OBJECT while ((iter = ++iter + (type == JSON_OBJECT)) < listLength) // necessary so we don't choke on next if test if (llGetListEntryType(values, iter) == TYPE_STRING) // make sure it is not a JSON_* Value or a Number if (llJsonValueType(llList2String(values, iter), []) == JSON_INVALID) values = llListReplaceList(values, ["\"" + llList2String(values, iter) + "\""], iter, iter);

return llList2Json(type, values); }

////////////////////////////// // function string uJsonSetValue ( string json, list specifiers, string value ) // This function takes the exact same parameters as // llJsonSetValue() but correctly encodes all possible strings // including those with escape characters within them. // // Initial strings must escape all instances of the // desired escape character itself // (ie "\\t" => '\t', "\\\\" => '\\', "\\/" => '\/') // as well as any double quotes ("\\\"" => '\"') // // NOTE: To encode a Float or Integer as a String // within the Json text, enclose it with escaped quotes // (ie '"3"' => '3' BUT '"\"3\""' => '"3"') // // Version 1.0 by LepreKhaun 9/19/2013 // May be freely used, modified and distributed with this header intact. /////////////////////////////// string uJsonSetValue(string json, list specifiers, string value) { // We don't want to change the string representation of // an integer, a float or any Json Value Type if (llJsonValueType(value, []) == JSON_INVALID) value = "\"" + value + "\""; return llJsonSetValue(json, specifiers, value); }


/////////// // Examples showing usage ///////////

default { touch_end(integer i) { string temp; string jsonText;

// To encode '{"A":"\"Go!\" he yelled.\nShe replied \"No!\"","Z":"\\escaped \\ slosh\\"}' jsonText = uList2Json (JSON_OBJECT, [ "A", "\\\"Go!\\\" he yelled.\\nShe replied \\\"No!\\\"", "Z", "\\\\escaped \\\\ slosh\\\\" ]); llOwnerSay(jsonText);

// To encode '{"Control Chars":"\b\r\f\n\t and Windows uses \r\n for EOL","©":"\u00A9"}' jsonText = uList2Json(JSON_OBJECT, [ "Control Chars", "\\b\\r\\f\\n\\t and Windows uses \\r\\n for EOL", "©", "\\u00A9" ]); llOwnerSay(jsonText);

// To encode '["WebSite","http:\/\/my.com\/ask.php?what%20is%20it","\t"]' jsonText = uList2Json(JSON_ARRAY, [ "WebSite", "http:\\/\\/my.com\\/ask.php?what%20is%20it", "\\t" ]); llOwnerSay(jsonText);

// Make a Json object... temp = uList2Json(JSON_OBJECT, [ "A", 99, "Z", "88]", "C", JSON_TRUE ]); // ... add it to end of the array ... jsonText = uJsonSetValue(jsonText, [JSON_APPEND], temp); // ... change our web address ... jsonText = uJsonSetValue(jsonText, [1], "http:\\/\\/www.google.com"); // ... change that TAB in the third spot to PI jsonText = uJsonSetValue(jsonText, [2], (string)PI); // ... and add a new "Key":Value pair to our object jsonText = uJsonSetValue(jsonText, [3, "New"], ((string)PI + "\\n"));

// ["WebSite","http:\/\/www.google.com",3.141593,{"A":99,"C":true,"New":"3.141593\n","Z":"88]"}] llOwnerSay(jsonText);

}

}</lsl>

Now, if I can just get the retrieval worked out as simply... ;=)


== More Json Tips, Tricks and Coding Examples ==