PHP's var_dump / print_r output is garbled - encoding issue? - php

I'm having a problem where on a server the output of var_dump and print_r come out entirely garbled. print_r outputs pure gibberish (eg. ��]{W�8�����- ... etc), while var_dump at least gives string (1664), followed by similar gibberish (though this time wrapped in double quotes).
This looks like a character encoding issue, but no encoding I can find seems to fix it (and I don't know why just dumping a PHP object should be outputting non-ascii characters anyway), and echo works fine. Alternatively, I wonder if it could be a gzip issue. Either way, I suspect it must be something in PHP or Apache's configuration, but I have no idea how to fix it.
I'd be very grateful if anyone has any suggestions as to how fix this!
Update: on further investigation, it seems it's a problem specific to the particular object I'm trying to dump. The object in question is decoded JSON requested (via curl) from an API. Is it possible that either json_decode or curl could be misconfigured / mangling the encoding?

For what it's worth, I finally got to the bottom of this problem (I think!)
The problem seems to be that the API's output was being run through json_decode whether it was JSON or not. MySQL errors were causing an error page, not a JSON response, which when run through json_decode (by the API-handling code that received it) before var_dump produced garbled character salad, as above.

Related

PHP json_decode returns null

I'm writing PHP code that uses a database. To do so, I use an array as a hash-map.
Every time content is added or removed from my DB, I save it to file.
I'm forced by my DB structure to use this method and can't use mysql or any other standard DB (School project, so structure stays as is).
I built two functions:
function saveDB($db){
$json_db = json_encode($db);
file_put_contents("wordsDB.json", $json_db);
} // saveDB
function loadDB(){
$json_db = file_get_contents("wordsDB.json");
return json_decode($json_db, true);
} // loadDB
When echo-ing the string I get after the encoding or after loading from file, I get a valid json (Tested it on a json viewer) Whenever I try to decode the string using json_decode(), I get null (Tested it with var_dump()).
The json string itself is very long (~200,000 characters, and that's just for testing).
I tried the following:
Replacing single/double-quotes with double/single-quotes (Without any backslashes, with one backslash and three backslashes. And any combination I could think of with a different number of backslashes in the original and replaced string), both manually and using str_replace().
Adding quotes before and after the json string.
Changing the page's encoding.
Decoding without saving to file (Right after encoding).
Checked for slashes and backslashes. None to be found.
Tried addslashes().
Tried using various "Escape String" variants.
json_last_error() doesn't work. I get no error number (Get null, not 0).
It's not my server, so I'm not sure what PHP version is used, and I can't upgrade/downgrade/install anything.
I believe the size has something to do with it, because small strings seem to work fine.
Thanks Everybody :)
In your JSON file change null to "null" and it will solve the problem.
Check if your file is UTF8 encoded. json_decode works with UTF8 encoded data only.
EDIT:
After I saw uploaded JSON data, I did some digging and found that there are 'null' key. Search for:
"exceeding":{"S01E01.html":{"2217":1}},null:{"S01E01.html":
Change that null to be valid property name and json_decode will do the job.
I had a similar problem last week. my json was valid according to jsonlint.com.
My json string contained a # and a & and those two made json_decode fail and return null.
by using var_dump(json_decode($myvar)) which stops right where it fails I managed to figure out where the problem was coming from.
I suggest var_dumping and using find dunction to look for these king of characters.
Just on the off chance.. and more for anyone hitting this thread rather than the OP's issue...I missed the following, someone had htmlentities($json) way above me in the call stack. Just ensure you haven't been bitten by the same and check the html source.
Kickself #124

Not able to parse this json

I am trying to parse the json output from
http://www.nyc.gov/portal/apps/311_contentapi/services/all.json
And my php json_decode returns a NULL
I am not sure where the issue is, I tried running a small subset of the data through JSONLint and it validated the json.
Any Ideas?
The error is in this section:
{
"id":"2002-12-05-22-24-56_000010083df0188b4001eb56",
"service_name":"Outdoor Electric System Complaint",
"expiration":"2099-12-31T00:00:00Z",
"brief_description":"Report faulty Con Edison equipment, including dangling or corroded power lines or "hot spots.""
}
See where it says "hot spots." in an already quoted string. Those "'s should've been escaped. Since you don't have access to edit the JSON perhaps you could do a search for "hot spots."" and replace it with \"hot spots.\"" like str_replace('"hot spots.""', '\\"hot spots.\\""\, $str); for as long as that's in there. Of course that only helps if this is a one time thing. If the site continues to make errors in their JSON output you'll have to come up with something more complex.
What I did to identify the errors in the JSON ...
Since faulty quoting is the first thing to look for, I downloaded the JSON to a text file, opened in a text editor (I used vim but any full featured editor would do), ran a search and replace that removed all characters except double-quote and looked at the result. It was clear that correct lines should have 4 double-quotes so I simply searched for 5 double-quotes together and found the first bad line. I noted the line number and then undid the search and replace to get the original file back and looked at that line. This gives you what you need to get the developers of the API to fix the JSON.
Writing code to automatically fix the bad JSON before giving it to json_decode() would be quite a bit harder but doable using techniques like those in another answer.
According to the PHP manual:
In the event of a failure to decode, json_last_error() can be used to determine the exact nature of the error.
Try calling it to see where the error is.

What is the significance of "czowOiIiOw=="

In my particular case, I'm getting this error after doing an ExpressionEngine update from 1.x to 2.x. There is a table that manages site preferences, and the data for each field is a serialized PHP array. After the update, any serialized array instead just says czowOiIiOw==. Googling this string brings up other non-ExpressionEngine-related site forums where end users are reporting seeing this string while being unable to login.
Does anyone have any idea what might be causing this, or have you seen anything like this before?
It's an encoding of a serialization of an empty string.
>>> 'czowOiIiOw=='.decode('base64')
's:0:"";'
Somehow your preferences got wiped.
that is base64 encoded. it's :
s:0:"";
It's a base64-encoded version of s:0:"", which is a serialized PHP empty string.
Decoding it as base64 it becomes:
s:0:"";
As you can see if you execute the following line, it is a serialized empty string:
echo serialize(""); // Outputs s:0:"";
echo base64_encode(serialize("")); // Outputs czowOiIiOw==
For further information on the serialization spec, see this generous commenter's work, specifically Strings:
Anatomy of a serialize()'ed value:
...
String
s:size:value;

Why doesn't jQuery.parseJSON() work on all servers?

Hey there, I have an Arabic contact script that uses Ajax to retrieve a response from the server after filling the form.
On some apache servers, jQuery.parseJSON() throws an invalid json excepion for the same json it parses perfectly on other servers. This exception is thrown only on chrome and IE.
The json content gets encoded using php's json_encode() function. I tried sending the correct header with the json data and setting the unicode to utf-8, but that didn't help.
This is one of the json responses I try to parse (removed the second part of if because it's long):
{"pageTitle":"\u062e\u0637\u0623 \u0639\u0646\u062f \u0627\u0644\u0625\u0631\u0633\u0627\u0644 !"}
Note: This language of this data is Arabic, that's why it looks like this after being parsed with php's json_encode().
You can try to make a request in the examples given down and look at the full response data using firebug or webkit developer tools. The response passes jsonlint!
Finally, I have two urls using the same version of the script, try to browse them using chrome or IE to see the error in the broken example.
The working example : http://namodg.com/n/
The broken example: http://www.mt-is.co.cc/my/call-me/
Updated: To clarify more, I would like to note that I manged to fix this by using the old eval() to parse the content, I released another version with this fix, it was like this:
// Parse the JSON data
try
{
// Use jquery's default parser
data = $.parseJSON(data);
}
catch(e)
{
/*
* Fix a bug where strange unicode chars in the json data makes the jQuery
* parseJSON() throw an error (only on some servers), by using the old eval() - slower though!
*/
data = eval( "(" + data + ")" );
}
I still want to know if this is a bug in jquery's parseJSON() method, so that I can report it to them.
Found the problem! It was very hard to notice, but I saw something funny about that opening brace... there seemed to be a couple of little dots near it. I used this JavaScript bookmarklet to find out what it was:
javascript:window.location='http://www.google.com/search?q=u+'+('000'+prompt('String?').charCodeAt(prompt('Index?')).toString(16)).slice(-4)
I got the results page. Guess what the problem is! There is an invisible character, repeated twice actually, at the beginning of your output. The zero width non-breaking space is also called the Unicode byte order mark (BOM). It is the reason why jQuery is rejecting your otherwise valid JSON and why pasting the JSON into JSONLint mysteriously works (depending on how you do it).
One way to get this unwanted character into your output is to save your PHP files using Windows Notepad in UTF-8 mode! If this is what you are doing, get another text editor such as Notepad++. Resave all your PHP files without the BOM to fix your problem.
Step 1: Set up Notepad++ to encode files in UTF-8 without BOM by default.
Step 2: Open each existing PHP file, change the Encoding setting, and resave it.
You should try using json2.js (it's on https://github.com/douglascrockford/JSON-js)
Even John Resig (creator of jQuery) says you should:
This version of JSON.js is highly recommended. If you're still using the old version, please please upgrade (this one, undoubtedly, cause less issues than the previous one).
http://ejohn.org/blog/the-state-of-json/
I don't see anything related to parseJSON()
The only difference I see is that in the working example a session-cookie is set(guess it is needed for the "captcha", the mathematical calculation), in the other example no session-cookie is set. So maybe the comparision of the calculation-result fails without the session-cookie.

Problem reading data from file special characters

My previous question and this question both are related a bit. please have a look at my previous question I did not found any other way to unserialize the data so coming with the string operation
I am able to get the whole content from file but not able to get the specific string from this content.
I want to search a specific string from these content but function stop working when the reach at first special character in the string. If I am searching something found before the special character the works properly.
String operation function of PHP not working properly when the encounter first special character in the string and stop processing immediately, Hence they does not give me the correct output.
Originally they looks like (^#)
:"Mage_Core_Model_Message_Collection":2:{s:12:"^#*^#_messages";a:0:{}s:20:"^#*^#_lastAddedMessage";N;}
but when I did echo they are display as ?
Here is the code what I tried
$file='/var/www/html/products/var/session/sess_ciktos8icvk11grtpkj3u610o3';
$contents=file_get_contents($file);
$contents=htmlspecialchars($contents);
//$contents=htmlentities($contents);
echo $contents;
$restData=strstr($contents,'"id";s:4:"');
echo $restData;
$id=substr($restData,0,strpos($restData,'"'));
echo $id;
I changed the default_charset to iso-8859-1 and also utf-8 but not working with both
Please let me know How I can resolve this.
Thanks.
These characters that you see as ^# are actually null bytes. They don't have any proper display, neither they are meant to be displayed - it's an internal representation of protected properties in the engine. You're not supposed to mess with them.
As for resolving, it'd be nice to know what kind of resolution you seek - what result are you trying to achieve?

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