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dicomtrolley.auth

Authentication mechanisms for DICOM servers

VitreaAuth

Bases: AuthBase

Can log in to a server running Vitrea Connection 8.2.0.1

Usage

Raises

DICOMTrolleyAuthError If logging in fails

Notes

Vitrea login returns an auth token, but for some reason this is not checked at all and instead all validation is done based on session token.

Source code in dicomtrolley/auth.py 
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class VitreaAuth(AuthBase):
    """Can log in to a server running Vitrea Connection 8.2.0.1

    Usage
    -----


    Raises
    ------
    DICOMTrolleyAuthError
        If logging in fails

    Notes
    -----
    Vitrea login returns an auth token, but for some reason this is not checked
    at all and instead all validation is done based on session token.
    """

    def __init__(self, login_url, user, password, realm):
        self.login_url = login_url
        self.user = user
        self.password = password
        self.realm = realm

    def response_hook(self, r, **kwargs):
        """Called before returning response. Try to log if not authenticated"""
        if r.status_code == 401:
            """Not logged in, try to log in and retry request"""
            # first log in. This should automatically save the session ID
            login_response = self.do_login_call(r.connection)
            request = r.request.copy()
            request.prepare_cookies(
                login_response.cookies
            )  # transfer manually here
            retry_response = r.connection.send(request, **kwargs)

            # history makes cookies persist in session
            retry_response.history.append(login_response)
            return retry_response
        else:
            return r

    def do_login_call(self, connection):
        """Log in to vitrea connection url

        Raises
        ------
        DICOMTrolleyAuthError
            If logging in fails
        """
        req = Request(
            method="POST",
            url=self.login_url,
            headers={
                "X-Userid": self.user,
                "X-Password": self.password,
                "X-Realm": self.realm,
            },
        )
        response = connection.send(req.prepare())
        if response.status_code != 200:
            raise DICOMTrolleyAuthError(
                f"login failed. {response.status_code}: {response.reason}"
            )
        return response

    def __call__(self, r):
        """Called before sending the request"""

        # Make sure keep alive because session is authenticated, not just the
        # connection
        r.headers["Connection"] = "Keep-Alive"
        r.register_hook("response", self.response_hook)
        return r

__call__(r)

Called before sending the request

Source code in dicomtrolley/auth.py 
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def __call__(self, r):
    """Called before sending the request"""

    # Make sure keep alive because session is authenticated, not just the
    # connection
    r.headers["Connection"] = "Keep-Alive"
    r.register_hook("response", self.response_hook)
    return r

do_login_call(connection)

Log in to vitrea connection url

Raises

DICOMTrolleyAuthError If logging in fails

Source code in dicomtrolley/auth.py 
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def do_login_call(self, connection):
    """Log in to vitrea connection url

    Raises
    ------
    DICOMTrolleyAuthError
        If logging in fails
    """
    req = Request(
        method="POST",
        url=self.login_url,
        headers={
            "X-Userid": self.user,
            "X-Password": self.password,
            "X-Realm": self.realm,
        },
    )
    response = connection.send(req.prepare())
    if response.status_code != 200:
        raise DICOMTrolleyAuthError(
            f"login failed. {response.status_code}: {response.reason}"
        )
    return response

response_hook(r, **kwargs)

Called before returning response. Try to log if not authenticated

Source code in dicomtrolley/auth.py 
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def response_hook(self, r, **kwargs):
    """Called before returning response. Try to log if not authenticated"""
    if r.status_code == 401:
        """Not logged in, try to log in and retry request"""
        # first log in. This should automatically save the session ID
        login_response = self.do_login_call(r.connection)
        request = r.request.copy()
        request.prepare_cookies(
            login_response.cookies
        )  # transfer manually here
        retry_response = r.connection.send(request, **kwargs)

        # history makes cookies persist in session
        retry_response.history.append(login_response)
        return retry_response
    else:
        return r

create_session(login_url, user, password, realm='DefaultSystemRealm')

Returns a requests Session that logs in to Vitrea automatically as needed.

Facilitates single-line session creation. For readable code

Parameters

login_url: str Call this url to log in user: str username password: str password realm: str, optional Vitrea realm to pass when logging in. Defaults to 'DefaultSystemRealm'

Source code in dicomtrolley/auth.py 
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def create_session(login_url, user, password, realm="DefaultSystemRealm"):
    """Returns a requests Session that logs in to Vitrea automatically as needed.

    Facilitates single-line session creation. For readable code

    Parameters
    ----------
    login_url: str
        Call this url to log in
    user: str
        username
    password: str
        password
    realm: str, optional
        Vitrea realm to pass when logging in. Defaults to 'DefaultSystemRealm'
    """
    session = requests.Session()
    session.auth = VitreaAuth(
        login_url=login_url, user=user, password=password, realm=realm
    )
    return session