Trying to send xml file using Python Requests to OpenStreetMap Overpass API
Question
I have an .xml request that can succesfully retrieve data from the OpenStreetMap Overpass API.
<?xml version="1.0" encoding="UTF-8"?>
<osm-script>
<query type="node">
<has-kv k="name" v="Bethesda"/>
<has-kv k="network" v="Washington Metro"/>
</query>
<query type="way">
<around radius="800"/>
<has-kv k="building"/>
</query>
<union>
<item/>
<recurse type="down"/>
</union>
<print/>
</osm-script>
All I'm trying (and failing) to do now is send this xml via the Python requests library (i'm open to other python solutions). I send the request below:
files = {'file': ('Bethesda.xml', open('Bethesda.xml', 'rb'))}
r = requests.post('http://overpass-api.de/api/interpreter', data=files)
print r.text
but get the following error message:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" lang="en"/>
<title>OSM3S Response</title>
</head>
<body>
<p>The data included in this document is from www.openstreetmap.org. The data is made available under ODbL.</p>
<p><strong style="color:#FF0000">Error</strong>: line 1: parse error: Unknown type "file" </p>
<p><strong style="color:#FF0000">Error</strong>: line 1: parse error: An empty query is not allowed </p>
<p><strong style="color:#FF0000">Error</strong>: line 1: parse error: Unknown type "=" </p>
<p><strong style="color:#FF0000">Error</strong>: line 1: parse error: An empty query is not allowed </p>
<p><strong style="color:#FF0000">Error</strong>: line 1: parse error: Unknown type "Bethesda" </p>
<p><strong style="color:#FF0000">Error</strong>: line 1: parse error: ';' expected - '&' found. </p>
<p><strong style="color:#FF0000">Error</strong>: line 2: parse error: Unexpected end of input. </p>
Which indicates the request successfully reaches the Overpass API and gets back an xml file, but it seems like the xml request wasn't successfully transferred. I've tried a few variations but can't do much better than this. Clearly, I'm not much with Python...
1 answers
solution1
4 ACCPTED 2013-05-18 16:57:51
You want the xml to be the body of the POST. When you pass in the dict, requests turns it into a url query string that isn't encoded correctly and isn't what the api wants anyway. Its very annoying in my opinion. Query strings and bodies are different beasts - they shouldn't be smooshed into a single parameter and automagically guestimated.
This works:
import requests
r = requests.post('http://overpass-api.de/api/interpreter',
data=open('Bethesda.xml', 'rb'))
print(r.text)
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