Error Handling
When errors/exceptions occur in the system, the API Manager throws XML-based error responses to the client by default. To change the format of these error responses, you change the relevant XML file in the <APIM_HOME>/repository/deployment/server/synapse-configs/default/sequences directory. The directory includes multiple XML files, named after the type of errors that occur. You must select the correct file.
For example, to change the message type of authorization errors, open the <APIM_HOME>/repository/deployment/server/synapse-configs/default/sequences/_auth_failure_handler.xml
file and change application/xml to something like application/json .
<sequence name="_auth_failure_handler_" xmlns="http://ws.apache.org/ns/synapse">
<property name="error_message_type" value="application/json"/>
<sequence key="_cors_request_handler_"/>
</sequence>Similarly, to change the error messages of throttling errors (e.g., quota exceeding), change the _throttle_out_handler_.xml file; resource mismatch errors, the _resource_mismatch_handler_.xml file, etc.
Given below are some error codes and their meanings.
API handlers error codes
Error code | Error Message | Description | Example |
|---|---|---|---|
| API blocked | This API has been blocked temporarily. Please try again later or contact the system administrators. | Invoke an API which is in the BLOCKED lifecycle state |
| Message throttled out | The maximum number of requests that can be made to the API within a designated time period is reached and the API is throttled for the user. | Invoke an API exceeding the tier limit |
| Hard limit exceeded | Hard throttle limit has been reached | Invoke an API exceeding the hard throttle limit |
| Resource level throttle out | Message is throttled out because resource level has exceeded | Sending/Receiving messages beyond authorized resource level |
| Application level throttle out | Message is throttled out because application level is exceeded | Sending/Receiving messages beyond authorized application level |
| Subscription level throttled out | Message throttled out due to subscription level throttling limit reached. | Sending/Receiving messages beyond configured throttling limit of subscription level policy. |
| Message blocked | Accessing an API which is blocked on user, IP, application, or API Context. | An admin user can block API invocations in real time by user, IP, application, or API context. The API invocation meets the blocked condition. |
| Custom policy throttled out | Message throttled out due to exceeding the limit configured through the custom throttling policy rules. | The API invocations meet custom throttle policy rules, exceeding the limits of the configured custom policy. |
| Message throttled out | Messaged throttled out because of exceeding the burst control/rate limit (requests per second) in the subscription level policy. | Sending/Receiving messages exceeding the configured burst control/rate limit within second. |
| Unclassified authentication failure | An unspecified error has occurred | Backend service for key validation is not accessible when trying to invoke an API |
| Invalid credentials | Invalid authentication information provided The error codes | When the access token is invalid or inactive. |
| Missing credentials | No authentication information provided | Accessing an API without Authorization: Bearer header |
| Incorrect access token type is provided | The access token type used is not supported when invoking the API. The supported access token types are application and user accesses tokens. See Access Tokens. | Invoke an API with application token, where the resource only allows application user tokens |
| No matching resource found in the API for the given request | A resource with the name in the request can not be found in the API. | Invoke an API resource that is not available |
| The requested API is temporarily blocked | Happens when the API user is blocked. | Invoke API resource with a subscription that has been blocked by the API publisher |
| Resource forbidden | The user invoking the API has not been granted access to the required resource. | Invoke an unsubscribed API |
| The subscription to the API is inactive | The status of the API has changed to an inaccessible/unavailable state. | Invoke an API resource with a subscription that has not yet been approved by the administrator. |
| The access token does not allow you to access the requested resource | Can not access the required resource with the provided access token. Check the valid resources that can be accessed with this token. | Invoke API resource with an access token that is not generated to be used with the resource's scope. |
| Incomplete payload | The payload sent with the request is too large and the client is unable to keep the connection alive until the payload is completely transferred to the API Gateway | Sending a large PDF file with the POST request |
Sequences error codes
Error code | Description |
|---|---|
| Production/sandbox key offered to the API with no production/sandbox endpoint |
| Server cannot process the request due to an error in the request sent by the client |
| No matching resource found in the API for the given request |
In addition to the above error codes, we have engaged Synapse-level error codes to the default fault sequence and custom fault sequences (e.g., _token_fault_.xml ) of the API Manager. For information, see Error Handling in WSO2 EI documentation.
The HTTP Status Codes and the corresponding error codes from the error responses are given below.
Transport error codes
Error Code | Detail |
|---|---|
101000 | Receiver input/output error sending |
101001 | Receiver input/output error receiving |
101500 | Sender input/output error sending |
101501 | Sender input/output error receiving |
101503 | Connection failed |
101504 | Connection timed out (no input was detected on this connection over the maximum period of inactivity) |
101505 | Connection closed |
101506 | NHTTP protocol violation |
101507 | Connection cancelled |
101508 | Request to establish new connection timed out |
101509 | Send abort |
101510 | Response processing failed |