Py2neo erroring for basic requests with neo4j

Drivers & Stacks
1

I have spent the last few months running neo4j on my local machine. I have been using py2neo to orchestrate the db with python. I have just switched to running the database on an aws ec2 instance and I am recieving errors whenever I try to send requests to the database. I am using the following simple code to test the database, this code works perfectly on my local machine.

from py2neo import *

neo4j_url = 'http://localhost:7474/'
user = 'neo4j'
pwd = 'neo4j'

graph = Graph(neo4j_url, auth=(user,pwd))
print(graph)
graph.run("Create (n:Person{name: 'Andy person'})")

This code errors with

Graph('http://localhost:7474')
Traceback (most recent call last):
  File "/home/ec2-user/KG_construction/kg-construction/KG_env/lib64/python3.8/site-packages/py2neo/client/http.py", line 443, in from_json
    content = json_loads(data, object_hook=JSONHydrant.json_to_packstream)
  File "/usr/lib64/python3.8/json/__init__.py", line 370, in loads
    return cls(**kw).decode(s)
  File "/usr/lib64/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib64/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "test_connection.py", line 9, in <module>
    graph.run("Create (n:Person{name: 'Andy person'})")
  File "/home/ec2-user/KG_construction/kg-construction/KG_env/lib64/python3.8/site-packages/py2neo/database.py", line 405, in run
    return self.auto().run(cypher, parameters, **kwparameters)
  File "/home/ec2-user/KG_construction/kg-construction/KG_env/lib64/python3.8/site-packages/py2neo/database.py", line 989, in run
    result = self._connector.auto_run(cypher, parameters,
  File "/home/ec2-user/KG_construction/kg-construction/KG_env/lib64/python3.8/site-packages/py2neo/client/__init__.py", line 1340, in auto_run
    return cx.auto_run(cypher, parameters, graph_name=graph_name, readonly=readonly)
  File "/home/ec2-user/KG_construction/kg-construction/KG_env/lib64/python3.8/site-packages/py2neo/client/http.py", line 177, in auto_run
    rs = HTTPResponse.from_json(r.status, r.data.decode("utf-8"))
  File "/home/ec2-user/KG_construction/kg-construction/KG_env/lib64/python3.8/site-packages/py2neo/client/http.py", line 445, in from_json
    raise_from(ProtocolError("Cannot decode response content as JSON"), error)
  File "<string>", line 3, in raise_from
py2neo.errors.ProtocolError: Cannot decode response content as JSON

Does anyone have idea why this error is occuring on my ec2 instance but not on my local machine?

2

Are you running the python code on the same EC2 instance? Even so, I doubt you can use local host to refer to the EC2 instance. Use the EC2 instances URL instead. See if that helps.

3

Yeah it's running on the same EC2 instance
It's definitely connecting to the instance correctly

The first line of the response shows that it's established a connection and the credentials are correct

Graph('http://localhost:7474')
4

That should be the bolt protocol not http. Can you try the neo4j protocol like "neo4j://localhost:7687" as the URL. The error is because the http is sending a browser response which is not expected by the driver which is expecting a json.

1 Like
5

I'm having a similar issue. Trying to run py2neo code which worked on a remote server on a localhost and getting :

ProtocolError: Cannot decode response content as JSON

6

If the issue is fixed, can you please mark it as solution?

Thanks

7

Yes, that fixed it! Thanks so much!

8

that works! Thx so much!!