Python JSON decode ValueError: Extra data:

Question

I'm having a problem trying to decode and print JSON I receive from a socket connection.

The full traceback:

C:\Users\Jeremy>python F:\Files\Python\test.py
2013-01-04 21:15:35 [INFO] [AutoSaveWorld] World save Complete!
2013-01-04 21:15:50 [INFO] [←[34;1mMain←[37;1m]←[32;22mRexOZ←[37;1m: you cahaned
 your house it looks awesome←[m
Traceback (most recent call last):
  File "F:\Files\Its safer indoors\Python\test.py", line 14, in <module>
    data = json.loads(dreceve)
  File "C:\Python33\lib\json\__init__.py", line 309, in loads
    return _default_decoder.decode(s)
  File "C:\Python33\lib\json\decoder.py", line 355, in decode
    raise ValueError(errmsg("Extra data", s, end, len(s)))
ValueError: Extra data: line 2 column 1 - line 3 column 1 (char 151 - 344)

As you can see the first 2 lines print fine and then it crashes.

Full code:

import socket
import json
import re

HOST = 'host.host.net'
PORT = 8082
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
dsend = "/api/subscribe?source=console&key=SUPERSEXYSECRETEY&show_previous=true\n"
s.sendall(dsend.encode())

while 1:
    dreceve = s.recv(1024).decode()
    data = json.loads(dreceve)
    succses = data['success']
    line = succses['line']
    print(line)

s.close()

I have goggled around for this error and the pages I found did not solve my problem, any help work be appreciated.

You'll need to show sample data that demonstrates the problem. — BrenBarn
– BrenBarn, Commented Jan 4, 2013 at 3:49
I would guess that the problem is that you're just reading chunks of 1024 bytes. The socket may send a chunk that is only a JSON fragment and not valid JSON in itself. You should try some other way to get the data (like those suggested by miku). — BrenBarn
– BrenBarn, Commented Jan 4, 2013 at 4:16
-1 for using raw sockets instead of using a decent module for fetching URLs. — user2665694
– user2665694, Commented Jan 4, 2013 at 5:24
@AndreasJung Really? Maybe if the question was bad or he displayed gross ignorance, but down-voting because he doesn't use "a decent module"? That's petty. — datu-puti
– datu-puti, Commented Mar 14, 2017 at 0:18

user3630337 · Accepted Answer · 2014-05-27 20:07:29Z

8

Whatever you receive, it does not seem to end where it should end; example:

>>> import json
>>> json.loads(""" {"Hello" : "World"} \ """)
....
ValueError: Extra data: line 1 column 21 - line 1 column 23 (char 21 - 23)

I'd suggest inspect your output before it gets parsed to get hold of the problem.

PS. There are simpler ways to get JSON data from a server (assuming your server returns parsable JSON, which it might not). Here is an example using the requests library:

>>> import json, requests
>>> u = "http://gdata.youtube.com/feeds/api/standardfeeds/most_popular?alt=json"
>>> json.loads(requests.get(u).text) # <-- request + parse
{u'feed': {u'category': [{u'term': u'http://gdata.youtube.com/...

.....

edited May 27, 2014 at 20:07

user3630337

32 bronze badges

answered Jan 4, 2013 at 4:00

miku

189k47 gold badges314 silver badges317 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

VxCoder · Accepted Answer · 2014-12-06 06:48:40Z

3

In the json lib ->decoder.py->decode function

if end != len(s):
       raise ValueError(errmsg("Extra data" , s , end , len(s)))

It's mean if your string's len != end , will raise this Exception And the end is the last "}" postion in your string. so you I can use:

string = "".join([string.rsplit("}" , 1)[0] , "}"])

cut the extra data after the last "}".

answered Dec 6, 2014 at 6:48

VxCoder

311 bronze badge

Comments

bl79 · Accepted Answer · 2017-12-20 22:38:22Z

0

Sometimes there may be ';' at tail of the JSON string. Just remove it:

json.loads(string.strip(';'))

answered Dec 20, 2017 at 22:38

bl79

1,4391 gold badge17 silver badges23 bronze badges

Collectives™ on Stack Overflow

Python JSON decode ValueError: Extra data:

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related