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 :)

Reputation: 165

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 :)

Upvotes: 2

Answers (4)

Cliffordlife

Reputation: 470

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

Upvotes: 0

Odinn

Reputation: 808

In your JSON file change null to "null" and it will solve the problem.

Upvotes: 3

Boris Belenski

Reputation: 1412

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.

Upvotes: 3

Rayfloyd

Reputation: 273

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.

Upvotes: 0

PHP json_decode returns null

Answers (4)

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