Http & Https Implementation

This drb-driver-http module implements http and https protocol access with DRB data model.

Http Factory and Http Node

The module implements the factory model defined in DRB in its node resolver. Based on the python entry point mechanism, this module can be dynamically imported into applications.

The entry point group reference is drb.driver.
The implementation name is http.
The factory class is encoded into drb.drivers.http.
The http signature id is b065a5aa-35a3-11ec-8d3d-0242ac130003
The https signature id is c18ef57c-3673-11ec-8d3d-0242ac130003

The HttpNode can be instantiated from an uri. The ParsedPath class provided in drb core module can help to manage these inputs.

Using this module

The project is present in https://www.pypi.org service. it can be freely loaded into projects with the following command line:

pip install drb-driver-http

Access Data

DrbHttpNode manages the http protocol to access remote data. The construction parameter is an url. Both http and https are supported. They allow access to the http content and header. The content is accessible with value node class attribute. It shall also be possible to retrieve specific streamed implementation using the get_impl method. The URL HTTP GET response header of the given URL is accessible via attributes of the node.

from drb.drivers.http import DrbHttpNode

node = DrbHttpNode('https://gitlab.com/drb-python/impl/http/-/raw/main/README.md')

print(node.name)
print(node.attributes)
print(node.path)
print(node.value)

HTTP protocol does not allow navigation inside http path so this implementation is not able to provide any children of the same HTTP type.

Authentication

Http node is able to manage Basic authentication based on username and password, as well as OAuth2.0 authentication based on token. It should also support Digest authentication via requests package HTTPDigestAuth implementation.

Basic Auth

To implements Basic authentication connection, the HTTPBasicAuth class from requests package is used.

from requests.auth import HTTPBasicAuth
from drb.drivers.http import DrbHttpNode

auth = HTTPBasicAuth('username', 'password')
node = DrbHttpNode('https://www.gael.fr', auth=auth)

OAuth2.0 connection

A dedicated HTTPOAuth2 class is available to manage OAuth2.0 authentication. It allows token retrieval and refresh when expired.

from drb.drivers.http import DrbHttpNode, HTTPOAuth2

svc_url = 'https://www.gael-systems.com/service'
token_svc = 'https://auth.gael-systems.com/token'
user = 'user'
password = 'pass'
service_id = 'service'
secret = 'secret'

auth = HTTPOAuth2(username=user, password=password, token_url=token_svc,
                  client_id=service_id, client_secret=secret)

node = DrbHttpNode(svc_url, auth=auth)

The renewal event of the token is triggered by computation. Based on the token expiration delay, the implementation computes the period to create or refresh a new token. Thanks to this mechanism, no unnecessary connection is performed by the client for this stage.

GDAL locator (gdal-vsi)

A node exposes a GDAL /vsicurl locator through get_impl(str, 'gdal-vsi') (/vsicurl/<url>), so a consumer such as drb-driver-image can let GDAL read the resource natively over HTTP range requests instead of downloading it whole. It composes under a container locator, e.g. /vsizip{/vsicurl/https://.../product.zip}/inner.jp2. When the node carries authentication (basic, OAuth2, ...), the Authorization header it produces is forwarded to GDAL's /vsicurl handler through the GDAL_HTTP_HEADERS environment variable (no GDAL import in this driver). This is process-global, so a single credential set is assumed per process.

Limitations

The HTTP protocol does not allow navigation inside an http path, so this implementation does not provide any children.

Documentation

The documentation of this implementation can be found here https://drb-python.gitlab.io/impl/http