I am making an ajax call and getting back result from array that looks like result = [one, two, three];
I need to convert this to an array and iterate it. Since my string has no quotes around values array isn't read correctly.
Here is my code, if you can please show me correct way to do it. Thanks.
xmlhttp.open("POST","SearchServlet", true);
xmlhttp.onreadystatechange =
function(){
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
resultData = xmlhttp.responseText;
// resultData = [one, two, three];
// need to make valid array to iterate it
for (var i = 0; i < resultData.length; i++) {
console.log(resultData[i]);
}
}
};
Hi "user" and welcome to SO. Thanks for the code sample and well-formatted question :)
Since HTTP requests use strings (they don't send arrays), the best way to send your response is in JSON format. You can then easily parse the JSON string into an array.
http://www.copterlabs.com/blog/json-what-it-is-how-it-works-how-to-use-it/
JSON is a really easy to use (usually) way to send strings and dump them into arrays and vice versa.
There's ways to do it in Java (which I assume is the language for your server-side code) and PHP (which many people use also) and every other language.
For some reason I recall the Java ones being more difficult to use than they should be, but hopefully I'm mistaken. Either way, it's not too hard to learn and will bring your code-fu to the next level for sure.
A hack-y, not correct, ugly way to do it using your raw string is:
// Remove first and last bracket
var data = resultData.substr(1, resultData.length - 2);
// Split the array
data = data.split(", ");
...but please don't do it this way, this is for educational purposes only (at the risk of a downvote). Also I haven't tested it but you get the idea.
Again, the best way to do it is change your design to use JSON everywhere.
Ideally, you would use the JSON.parse function, but since one, two, and three are not quoted, you will have to do some work.
You can run through each of the items in your square brackets and put double quotes around them, then call JSON.parse. Alternatively, do as Steve suggests and rewrite your server's handler to respond with proper JSON.
If they were quoted, JSON.parse would work like this:
> JSON.parse('["one", "two", "three"]')
["one", "two", "three"]
Try this, its a little more complex, but it'll work:
resultData = xmlhttp.responseText;
resultData = resultData.substring(1, resultData.length-1);
var resultArray = resultData.split(',');
Though I don't know exactly why you can't output a valid JSON (with quoted strings in your array), this little and dirty function can parse your "almost-array" to a valid one, by putting quotes and removing spaces, this function returns a real array.
function validArray(str){
return str
.replace(/[\[\]']+/g,"")
.split(",")
.map(function(v){
return v.replace(/^\s\s*/g, '').replace(/\s\s*$/g, '');
});
}
The best solution is to avoid this kind of parsing and respond with valid JSON. This way, you could simply do a JSON.parse and easily obtain a JS object.
Related
I am working on a Node.js application that needs to handle JSON strings and work with the objects.
Mostly all is well and JSON.parse(myString) is all I need.
The application also gets data from third parties. One of which seems to be developed with Python.
My application repeatable chokes on boolean values since they come captialized.
Example:
var jsonStr = "{'external_id': 123, 'description': 'Run #2944', 'test_ok': False}";
try{
var jsonObj = JSON.parse(jsonStr);
}catch(err){
console.err('Whoops! Could not parse, error: ' + err.message);
}
Notice the test_ok parameter - it all is good when it follows the Javascript way of having a lower case false boolean instead. But the capitalized boolean does not work out.
Of course I could try and replace capitalized boolean values via a string replace, but I am afraid to alter things that should not get altered.
Is there an alternative to JSON.parse that is a little more forgiving?
I don't mean to be rude but according to json.org, its an invalid json. That means you'll have to run a hack where you have to identify stringified boolean "True" and convert it to "true" without affecting a string that lets say is "True dat!"
First of all, I would not recommend using the code below. This is just to demonstrate how to convert your input string into a valid JSON. There were problems, one is the Boolean False, and another is the single quotes around property names. I'm not positive but I believe those need to be double quotes.
I don't believe having to convert a string into a valid JSON is a good choice. If you have no alternative, meaning you don't have access to the code generating this string, then the code below is still not a good choice because it will have issues if you have embedded quotes in the string values. i.e. you would need different string replace logic.
Keep all this in mind before using the code.
var jsonStr = "{'external_id': 123, 'description': 'Run #2944', 'test_ok': False}";
try {
jsonStr = jsonStr.replace(/:[ ]*False/,':false' ).replace( /'/g,'"');
var jsonObj = JSON.parse(jsonStr);
console.log( jsonObj );
} catch (err) {
console.err('Whoops! Could not parse, error: ' + err.message);
}
I'm receiving a string like obj{a="foo",b="bar",c=3,d=4.0} inside a nodejs environment I'm working in and I'm trying to convert this String into a reference-able Object like this:
{
a : "foo",
b : "bar",
c : 3,
d : 4.0
}
Assigned to obj of course.
I've used a myriad of formatting tricks but whenever I call JSON.parse() I get unexpected character errors. Usually on the first alpha-character it sees.
My next step is to write several nested loops to make all of the assignments manually but I'm hoping someone can point me in the right direction on how to parse this.
EDIT: Ok there's a little more to the story and I thought I should omit it but I guess explaining everything would be helpful.
The actual data packet that I'm receiving looks like this.
ack{a="000000061",b=0,c=2.0}\rb{a=244.0,b=255,c=4.0}\rc{a=6.0,b=55,c=55}endack;
So yeah that's the actual string I'm trying to parse into three distinct accessible Objects. I know I'm having a brain fart from a long day but yeah it's giving me a run for my money right now.
First replace the "=" with ":" and remove the obj infront
str = str.replace(/=/g, ":").replace("obj{", "{")
Since it's not in correct json format (but can be read by js parser) we can't use JSON.parse but we can use eval
eval("var obj = " + str);
Obvious there are some assumptions with this technique such that = always mean colon and you won't have obj{ as text (but the latter can be fixed with a simple substring method)
Keep in mind eval is also considered evil so use at your own risk. Imagine if the user were to send bad data, they could easily get into your parser and run something malicious. But hopefully this will give you an idea or inspiration to a better solution.
You can go a step further and use
str = 'obj{a="foo",b="bar",c=3,d=4.0}'
str = str.substr(3,str.length).replace(/([{,])([\w])=/g, '$1\"$2\":');
var obj = JSON.parse(str);
I am being sent an ill formed JSON string from a third party. I tried using JSON.parse(str) to parse it into a JavaScript object but it of course failed.
The reason being is that the keys are not strings:
{min: 100}
As opposed to valid JSON string (which parses just fine):
{"min": 100}
I need to accept the ill formed string for now. I imagine forgetting to properly quote keys is a common mistake. Is there a good way to change this to a valid JSON string so that I can parse it? For now I may have to parse character by character and try and form an object, which sounds awful.
Ideas?
You could just eval, but that would be bad security practice if you don't trust the source. Better solution would be to either modify the string manually to quote the keys or use a tool someone else has written that does this for you (check out https://github.com/daepark/JSOL written by daepark).
I did this just recently, using Uglifyjs to evaluate:
var jsp = require("uglify-js").parser;
var pro = require("uglify-js").uglify;
var orig_code = "var myobject = " + badJSONobject;
var ast = jsp.parse(orig_code); // parse code and get the initial AST
var final_code = pro.gen_code(ast); // regenerate code
$('head').append('<script>' + final_code + '; console.log(JSON.stringify(myobject));</script>');
This is really sloppy in a way, and has all the same problems as an eval() based solution, but if you just need to parse/reformat the data one time, then the above should get you a clean JSON copy of the JS object.
Depending on what else is in the JSON, you could simply do a string replace and replace '{' with '{"' and ':' with '":'.
I have a variable called "result",
var result;
that result value is equal to following value, please presume that is just a string :)
---------result value -----------
for (;;);{
"send":1,
"payload":{
"config":{
"website":"",
"title":"welcome to site",
"website-module":1313508674538,
"manufatureid":"id.249530475080015",
"tableid":"id.272772962740259",
"adminid":100002741928612,
"offline":null,
"adminemail":"admin#website.com",
"adminame":"George",
"tags":"web:design:template",
"source":"source:design:web",
"sitelog":[],
"errorlog":0,
"RespondActionlog":0,
"map":null
},
"imgupload":""
},
"criticalerror":[0],
"report":true
}
---------result value------------
From that value, I would like to extract tableid which is "id.272772962740259" with classic Javascript.
How can I extract the code, please let me know how can i do with simple javascript, please don't use Jquery, all I just need is simple javascript.
You can simply evaluate the value of the variable to obtain the values. However, please note that your current value is not valid JSON; that for(;;); at the beginning of the value invalidates the format. Remove that, and you can do this:
var object = eval('(' + resultMinusThatForLoop + ')');
alert(object.payload.config.tableid);
If that data is a string the parse it with a JSON parse. The following should get the value you want
JSON.parse(result).payload.config.tableid; // "id.272772962740259"
Edit: though, as Tejs says, the for(;;) invalidates the string and stops it from being parsed. If you can remove that, do.
You need to remove the empty for loop, then parse the string. DO NOT use eval; most modern browsers provide built-in JSON-parsing facilities, but you can use json2.js if yours does not. Assuming that you assign the results of parsing the JSON to result, you should be able to get that value using result.payload.config.tableid.
You should probably read a good JS reference. JavaScript: The Good Parts or Eloquent JavaScript would be a good choice.
If result is a javascript object and not a string, you can just use 'result.payload.config.tableid'.
If it is not, how do you get the AJAX result? Are you using XmlHttpRequest directly? Most libraries will give you a javascript object, you might be missing a flag or not sending the response back with the right content type.
If it is a string and you want to parse it manually, you should use a JSON parser. Newer browsers have one built in as window.JSON, but there is open source code for parsing it as well.
var obj = JSON.parse(result);
alert('tableid is ' + obj.payload.config.tableid);
I am parsing a json string like so:
ring = JSON.parse(response);
Now, ring is an object but ring.stones is just a string when it should be an object as well.
If I call:
ring.stones = JSON.parse(ring.stones);
It is now the correct object.
I didn't know if this is correct behavior or if maybe I have an issue somewhere stopping it from parsing recursively? If it is supposed to parse recursively, are there any known issues that would prevent it?
Update
Here is the full response before parsing:
{"ring_id":"9","stone_count":"4","style_number":"style 4","syn10":"436.15","gen10":"489.39","syn14":"627.60","gen14":"680.85","available":"yes","type":"ring","engravings_count":"0","engravings_char_count":"0","engravings_band":"10","stones":"[{\"stone_id\":\"27\",\"ring_id\":\"9\",\"stone_shape\":\"round\",\"stone_x\":\"132.80\",\"stone_y\":\"114.50\",\"stone_width\":\"71.60\",\"stone_height\":\"71.60\",\"stone_rotation\":\"0.00\",\"stone_number\":\"1\",\"stone_mm_width\":\"5.00\",\"stone_mm_height\":\"5.00\"},{\"stone_id\":\"28\",\"ring_id\":\"9\",\"stone_shape\":\"round\",\"stone_x\":\"100.50\",\"stone_y\":\"166.20\",\"stone_width\":\"36.20\",\"stone_height\":\"36.60\",\"stone_rotation\":\"0.00\",\"stone_number\":\"2\",\"stone_mm_width\":\"2.50\",\"stone_mm_height\":\"2.50\"},{\"stone_id\":\"29\",\"ring_id\":\"9\",\"stone_shape\":\"round\",\"stone_x\":\"200.20\",\"stone_y\":\"105.10\",\"stone_width\":\"33.90\",\"stone_height\":\"33.90\",\"stone_rotation\":\"0.00\",\"stone_number\":\"3\",\"stone_mm_width\":\"2.50\",\"stone_mm_height\":\"2.50\"},{\"stone_id\":\"30\",\"ring_id\":\"9\",\"stone_shape\":\"round\",\"stone_x\":\"165.80\",\"stone_y\":\"82.50\",\"stone_width\":\"35.50\",\"stone_height\":\"33.90\",\"stone_rotation\":\"0.00\",\"stone_number\":\"4\",\"stone_mm_width\":\"2.50\",\"stone_mm_height\":\"2.50\"}]","images":"[{\"title\":\"white gold\",\"source\":\"Style4_4_W_M.png\"},{\"title\":\"yellow gold\",\"source\":\"Style4_4_Y_M.png\"}]"}
Update 2
Based on mikerobi's answer I was able to figure out what was happening:
Here is where I encoded it:
$row = $sth->fetch(PDO::FETCH_ASSOC);
$row['stones'] = getStones($ring_id);
$row['images'] = getRingVariations($ring_id);
return json_encode($row);
But the functions getStones and getRingVariations were returning json_encode'd strings. I needed to change them to return plain strings.
Your JSON structure is wrong, it is wrapping stones in quotes, turning it into a string.
Your JSON looks like:
{
stones: "[{\"stone_id":\"27\"},{\"stone_id\":\"27\"}]"
}
It should look like:
{
stones: [{"stone_id": 27},{"stone_id": 27}]
}
EDIT
It appears you are converting all values to string, including numbers, I updated my example to reflect this.
Also, I'm guessing by the output that you are writing your own code to serialize the JSON, I highly recommend using an existing library.
It is recursive, but your input string (response) is not in correct format. Get rid of those escape characters (\") and try again.