The following Python code example demonstrates how to configure a connection to download data from an Earthdata Login enabled server. Note that you will need to a secure way to configure the Earthdata Login username and password.
#!/usr/bin/python from cookielib import CookieJar from urllib import urlencode import urllib2 # The user credentials that will be used to authenticate access to the data username = "<Your Earthdata login username>" password = "<Your Earthdata login password>" # The url of the file we wish to retrieve url = "http://e4ftl01.cr.usgs.gov/MOLA/MYD17A3H.006/2009.01.01/MYD17A3H.A2009001.h12v05.006.2015198130546.hdf.xml" # Create a password manager to deal with the 401 reponse that is returned from # Earthdata Login password_manager = urllib2.HTTPPasswordMgrWithDefaultRealm() password_manager.add_password(None, "https://urs.earthdata.nasa.gov", username, password) # Create a cookie jar for storing cookies. This is used to store and return # the session cookie given to use by the data server (otherwise it will just # keep sending us back to Earthdata Login to authenticate). Ideally, we # should use a file based cookie jar to preserve cookies between runs. This # will make it much more efficient. cookie_jar = CookieJar() # Install all the handlers. opener = urllib2.build_opener( urllib2.HTTPBasicAuthHandler(password_manager), #urllib2.HTTPHandler(debuglevel=1), # Uncomment these two lines to see #urllib2.HTTPSHandler(debuglevel=1), # details of the requests/responses urllib2.HTTPCookieProcessor(cookie_jar)) urllib2.install_opener(opener) # Create and submit the request. There are a wide range of exceptions that # can be thrown here, including HTTPError and URLError. These should be # caught and handled. request = urllib2.Request(url) response = urllib2.urlopen(request) # Print out the result (not a good idea with binary data!) body = response.read() print body
Here is another example that will only work with later versions of python:
#!/usr/bin/python import requests # get the requsts library from https://github.com/requests/requests # overriding requests.Session.rebuild_auth to mantain headers when redirected class SessionWithHeaderRedirection(requests.Session): AUTH_HOST = 'urs.earthdata.nasa.gov' def __init__(self, username, password): super().__init__() self.auth = (username, password) # Overrides from the library to keep headers when redirected to or from # the NASA auth host. def rebuild_auth(self, prepared_request, response): headers = prepared_request.headers url = prepared_request.url if 'Authorization' in headers: original_parsed = requests.utils.urlparse(response.request.url) redirect_parsed = requests.utils.urlparse(url) if (original_parsed.hostname != redirect_parsed.hostname) and \ redirect_parsed.hostname != self.AUTH_HOST and \ original_parsed.hostname != self.AUTH_HOST: del headers['Authorization'] return # create session with the user credentials that will be used to authenticate access to the data username = "USERNAME" password= "PASSWORD" session = SessionWithHeaderRedirection(username, password) # the url of the file we wish to retrieve url = "http://e4ftl01.cr.usgs.gov/MOLA/MYD17A3H.006/2009.01.01/MYD17A3H.A2009001.h12v05.006.2015198130546.hdf.xml" # extract the filename from the url to be used when saving the file filename = url[url.rfind('/')+1:] try: # submit the request using the session response = session.get(url, stream=True) print(response.status_code) # raise an exception in case of http errors response.raise_for_status() # save the file with open(filename, 'wb') as fd: for chunk in response.iter_content(chunk_size=1024*1024): fd.write(chunk) except requests.exceptions.HTTPError as e: # handle any errors here print(e)
Here is another simple example:
# assuming variables `username`, `password` and `url` are set... # Example URL url = "https://n5eil01u.ecs.nsidc.org/MOST/MOD10A1.006/2016.12.31/" # url = "https://e4ftl01.cr.usgs.gov/MOTA/MCD43A2.006/2017.09.04/" import requests with requests.Session() as session: s.auth = (username, password) r1 = session.request('get', url) r = session.get(r1.url, auth=(username, password)) if r.ok: print r.content # Say
Accessing Data from NSIDC:
NSIDC has provided sample scripts to access their data with Python: