feat: Add Pagination for requesting list of prompts #140
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Adds the Pagination feature to the `prompts/list` feature as described in the specification. To make this possible mainly two changes are made: 1. The logic for cursor handling is added. 2. Handling for invalid parameters (MCP error code `-32602 (Invalid params)`) is added to the `McpServerSession`. For now the cursor is the base64 encoded start index of the next page. The page size is set to 10. When parameters are found to be invalid the newly introduced `McpParamsValidationError` is returned to handle it properly in the `McpServerSession`.
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| var errorCode = McpSchema.ErrorCodes.INTERNAL_ERROR; | ||
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| if (error instanceof McpParamsValidationError) { |
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I suspect we have some convoluted handling of McpError here and on the client side too, but we can address this later on and clean up.
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| public class McpParamsValidationError extends McpError { | ||
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| public McpParamsValidationError(McpSchema.JSONRPCResponse.JSONRPCError jsonRpcError) { |
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It feels that we don't need this constructor at this time. Let's remove it.
| super(jsonRpcError.message()); | ||
| } | ||
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| public McpParamsValidationError(Object error) { |
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This can be a string at the moment I believe.
| new TypeReference<McpSchema.PaginatedRequest>() { | ||
| }); | ||
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| if (!isCursorValid(request.cursor(), this.prompts.size())) { |
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We can nest this under the request.cursor() != null and avoid returning true inside the validation method.
| int requestedStartIndex = 0; | ||
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| if (request.cursor() != null) { | ||
| requestedStartIndex = decodeCursor(request.cursor()); |
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I think we could take into account the hash of the prompts collection and based on the page size infer whether the collection has not changed - if it has we should return an error allowing the client to restart fetching the results.
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Hi, thanks for your review and your feedback!
Yes I will do this. I should be able to update the pull request by the end of the week. |
Adds the Pagination feature to the
prompts/listfeature to fulfil the specification.Motivation and Context
This adds the Pagination feature to the
prompts/listfeature as described in the specification.To make this possible mainly two changes are made:
-32602 (Invalid params)) is added to theMcpServerSession.Decisions made:
base64string.10.McpParamsValidationErroris returned to handle it properly in theMcpServerSession.If this change is ok, I'm happy to create a follow-up PR for the other MCP features. Maybe some parts of the cursor handling can be moved out to separate methods.
How Has This Been Tested?
Integration tests are added for the
prompts/listfeature.Types of changes
Checklist