BasicAuthentication policy runtime error troubleshooting

UnresolvedVariable

Error code

steps.basicauthentication.UnresolvedVariable

Error response body

{
    "fault": {
        "faultstring": "Unresolved variable : [variable_name]",
        "detail": {
            "errorcode": "steps.basicauthentication.UnresolvedVariable"
        }
    }
}

Example Error Message

{
    "fault": {
        "faultstring": "Unresolved variable : request.header.Authorization",
        "detail": {
            "errorcode": "steps.basicauthentication.UnresolvedVariable"
        }
    }
}

Cause

This error occurs if the variable containing the Base64 encoded string specified in the <Source> element of the BasicAuthentication policy is either:

  • Out of scope (not available in the specific flow where the policy is being executed)
  • Can't be resolved (is not defined)

For example, this error occurs if the BasicAuthentication policy has a variable specified asrequest.header.Authorization in the<Source> element, but the Authorization header is not passed as part of the API request.

Diagnosis

  1. Identify the variable used for the <Source> element in the BasicAuthentication policy. You can find this information in the faultstring element of the error response. For example, in the following faultstring, the variable used for <Source> element is request.header.Authorization:

    "faultstring": "Unresolved variable : request.header.Authorization"
    
  2. Examine all the BasicAuthentication policies in the specific API Proxy where the failure has occurred. There could be one or more BasicAuthentication policies. Identify the specific BasicAuthentication policy or policies in which the variable specified in the <Source> element matches the variable name identified in the fault string (step #1 above).

    For example, the following policy sets the <Source> element to a variable named request.header.Authorization, which matches what's in the faultstring:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <BasicAuthentication name="DecodeBaseAuthHeaders">
      <DisplayName>Decode Basic Authentication Header</DisplayName>
      <Operation>Decode</Operation>
      <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
      <User ref="request.header.username"/>
      <Password ref="request.header.password"/>
      <Source>request.header.Authorization</Source>
    </BasicAuthentication>
    
  3. Determine if the variable is defined and available in the flow in which the BasicAuthentication policy is being executed.

  4. If the variable is either:

    1. Out of scope (not available in the specific flow where the policy is being executed)
    2. Can't be resolved (is not defined)

    Then that's the cause for the error.

    In the example BasicAuthentication policy shown above, the variable request.header.Authorizationwas not passed as part of the request. That is, the API request was made without the Authorization header as shown below:

    curl -v "http://org-env.apigee.net/basicauth"

    Since the variable used in the BasicAuthentication policy is not available, you receive the error code:

    steps.basicauthentication.UnresolvedVariable
    

Resolution

Ensure that the variable used in the BasicAuthentication policy is defined or passed as an input and available in the flow where the policy is being executed.

To fix the issue with the sample BasicAuthentication policy discussed above, make an API request as shown below:

curl -v "http://org-env.apigee.net/basicauth" -H "Authorization: Basic YWthc2g6MTIz"

InvalidBasicAuthenticationSource

Error code

steps.basicauthentication.InvalidBasicAuthenticationSource

Error response body

{
    "fault": {
        "faultstring": "Source variable : [variable_name] for basic authentication decode policy is not valid",
        "detail": {
            "errorcode": "steps.basicauthentication.InvalidBasicAuthenticationSource"
        }
    }
}

Error Example Error Message

{
    "fault": {
        "faultstring": "Source variable : request.header.Authorization for basic authentication decode policy is not valid",
        "detail": {
            "errorcode": "steps.basicauthentication.InvalidBasicAuthenticationSource"
        }
    }
}

Possible causes

The possible causes for this error are:

Cause Description
Invalid source variable The input source variable to BasicAuthentication Policy is not a valid Base64 encoded string.
Header is Malformed The header containing the Base64 encoded string passed to BasicAuthentication policy is malformed.

Cause: Invalid source variable

This error occurs if the variable containing the Base64 encoded string specified in the <Source> element of the BasicAuthentication policy does not contain a valid value.

For example, this error occurs if the variable specified in the<Source> element of BasicAuthentication policy does not have a valid Base64 encoded string.

Diagnosis

  1. Identify the variable used for the <Source> element in the BasicAuthentication policy. You can find this information in the faultstring element of the error response. For example, in the following faultstring, the variable used for <Source> element is request.header.Authorization:

    "faultstring": "Source variable : request.header.Authorization for basic authentication decode policy is not valid"
    
  2. Examine all the BasicAuthentication policies in the specific API Proxy where the failure has occurred. There could be one or more BasicAuthentication policies. Identify the specific BasicAuthentication policy (ies) in which the variable specified in the <Source> element matches the variable name identified in the fault string (step #1 above).

    For example, the following policy sets the <Source> element to a variable named request.header.Authorization, which matches what's in the faultstring:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <BasicAuthentication name="DecodeBaseAuthHeaders">
        <DisplayName>Decode Basic Authentication Header</DisplayName>
        <Operation>Decode</Operation>
        <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
        <User ref="request.header.username"/>
        <Password ref="request.header.password"/>
        <Source>request.header.Authorization</Source>
    </BasicAuthentication>
    
  3. If the value stored in the variable specified in <Source> element is not a valid Base64 encoded string, thenthat's the cause for the error.

    In the example BasicAuthentication policy shown above, the variable request.header.Authorizationthat was sent by the client as a header was invalid as shown below:

    curl -v "http://org-env.apigee.net/basicauth" -H "Authorization: Basic 23435"

    Since the variable request.header.Authorizationhas an invalid Base64 encoded string "23435", you receive the error code:

    steps.basicauthentication.InvalidBasicAuthenticationSource

Resolution

Ensure that the variable specified for <Source> element in the BasicAuthentication policy has a valid Base64 encoded string.

To fix the issue with the sample BasicAuthentication policy discussed above, make an API request by passing a valid Base64 encoded string in the Authorization header as shown below:

curl -v "http://org-env.apigee.net/basicauth" -H "Authorization: Basic YWthc2g6MTIz"

Cause: Header is Malformed/invalid

This error occurs if the header passed to the BasicAuthentication policy is malformed or invalid.

For example, this error occurs if the BasicAuthentication policy has a variable specified asrequest.header.Authorization in the<Source> element and the header passed as part of the API request is malformed/invalid.

Diagnosis

  1. Identify the variable used for the <Source> element in the BasicAuthentication policy. You can find this information in the faultstring element of the error response. For example, in the following error, the variable used for <Source> element is request.header.Authorization:

    "faultstring": "Source variable : request.header.Authorization for basic authentication decode policy is not valid"
    
  2. Examine all the BasicAuthentication policies in the specific API Proxy where the failure has occurred. There could be one or more BasicAuthentication policies. Identify the specific BasicAuthentication policy (ies) in which the variable specified in the <Source> element matches the variable name identified in the fault string (step #1 above).

    For example, the following policy sets the <Source> element to a variable named request.header.Authorization, which matches what's in the faultstring:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <BasicAuthentication name="DecodeBaseAuthHeaders">
        <DisplayName>Decode Basic Authentication Header</DisplayName>
        <Operation>Decode</Operation>
        <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>
        <User ref="request.header.username"/>
        <Password ref="request.header.password"/>
        <Source>request.header.Authorization</Source>
    </BasicAuthentication>
    
  3. If the variable is a header and is malformed or invalid, i.e., it does not have the authentication type or if the authentication type is not "Basic", then that's the cause for the error.

    The Authorization header is of this form:

    Authorization: <Authentication type> <credentials>
    

    A malformed header can be passed to BasicAuthentication policy in two ways:

    Example 1: No Authentication type in the Header:

    curl -v "http://org-env.apigee.net/basicauth" -H "Authorization: YWthc2g6MTIz"

    In the above example, the Authorization header does not have the Authentication type. If this header is passed to BasicAuthentication policy shown above, you receive the error code:

    steps.basicauthentication.InvalidBasicAuthenticationSource
    

    Example 2: Authentication type is not of type "Basic":

    curl -v "http://org-env.apigee.net/basicauth" -H "Authorization: OAuth YWthc2g6MTIz"

    In the above example, the Authorization header does not have the Authentication type of "Basic". If this is passed to BasicAuthentication policy shown above, you receive the error code:

    steps.basicauthentication.InvalidBasicAuthenticationSource
    

    Similarly, this error can also occur if the Authentication type such as Bearer, Digest Auth, etc is used in the Authorization header.

Resolution

Ensure that the header in which the input to the BasicAuthentication policy is passed has the Authentication type and is of type "Basic".

To fix the issue with the sample BasicAuthentication policy discussed above, make an API request by passing a valid Base64 encoded string with "Basic" Authentication type in the Authorization header as shown below:

curl -v "http://org-env.apigee.net/basicauth" -H "Authorization: Basic YWthc2g6MTIz"