get_or_post.py

import requests
from chembl_webresource_client import *

# For some special SMILES, using GET method against webservices will end up with failure:

res = requests.get('https://www.ebi.ac.uk/chemblws/compounds/smiles/CN1C\C(=C/c2ccc(C)cc2)\C3=C(C1)C(C(=C(N)O3)C#N)c4ccc(C)cc4')
print res.ok
False

print res.status_code
400

# This is because the SMILES contain slash '/' character, which has a special meaning in URL.
# The solution to this problem is to use POST request, which will look like this:

res = requests.post('https://www.ebi.ac.uk/chemblws/compounds/smiles', data={'smiles':'CN1C\C(=C/c2ccc(C)cc2)\C3=C(C1)C(C(=C(N)O3)C#N)c4ccc(C)cc4'}, headers={'Accept':'application/xml'})�
print res.ok
True

print res.content
"<?xml version='1.0' encoding='utf-8'?>\n<list><compound><smiles>CN1C\\C(=C/c2ccc(C)cc2)\\C3=C(C1)C(C(=C(N)O3)C#N)c4ccc(C)cc4</smiles>..."


# In that case maybe it's better to use POST for all requests to ChEMBL?
# Unfortunately (currently) there are only a few methods (search by SMILES, substructure and similarity serach) 
# which support POST. Besides, GET requests contain all necessary data in the URL and such an URL can be embedded 
# on a website, send by email or chat, so in some cases they are more useful then POST.
# But if we have a large number of SMILES, deciding whether GET or POST should be used for each one of them can be 
# problematic. Our client can transparently handle this problem:

compounds = CompoundResource()

# Getting compound by SMILES containing only safe characters...

cs = compounds.get(smiles='COc1ccc2[C@@H]3[C@H](COc2c1)C(C)(C)OC4=C3C(=O)C(=O)C5=C4OC(C)(C)[C@@H]6COc7cc(OC)ccc7[C@H]56')
print cs[0]['molecularFormula']
'C32H32O8'

# ...looks exaclty the same as using SMILES with some unsafe characters such as slash:
cs = compounds.get(smiles="C\C(=C/C=C/C(=C/C(=O)O)/C)\C=C\C1=C(C)CCCC1(C)C")
print cs[0]['preferredCompoundName']
'MMAOIAFUZKMAOY-UHFFFAOYSA-N'