import { ConnectorManager } from "../connectors/manager.js";
import { Variables } from "@modelcontextprotocol/sdk/shared/uriTemplate.js";
import {
createResourceSuccessResponse,
createResourceErrorResponse,
} from "../utils/response-formatter.js";
/**
* Schema resource handler
* Returns schema information for a specific table, optionally within a specific database schema
*/
export async function tableStructureResourceHandler(uri: URL, variables: Variables, _extra: any) {
const connector = ConnectorManager.getCurrentConnector();
// Handle tableName which could be a string or string array from URL template
const tableName = Array.isArray(variables.tableName)
? variables.tableName[0]
: (variables.tableName as string);
// Extract schemaName if present
const schemaName = variables.schemaName
? Array.isArray(variables.schemaName)
? variables.schemaName[0]
: (variables.schemaName as string)
: undefined;
try {
// If a schema name was provided, verify that it exists
if (schemaName) {
const availableSchemas = await connector.getSchemas();
if (!availableSchemas.includes(schemaName)) {
return createResourceErrorResponse(
uri.href,
`Schema '${schemaName}' does not exist or cannot be accessed`,
"SCHEMA_NOT_FOUND"
);
}
}
// Check if the table exists in the schema before getting its structure
const tableExists = await connector.tableExists(tableName, schemaName);
if (!tableExists) {
const schemaInfo = schemaName ? ` in schema '${schemaName}'` : "";
return createResourceErrorResponse(
uri.href,
`Table '${tableName}'${schemaInfo} does not exist or cannot be accessed`,
"TABLE_NOT_FOUND"
);
}
// Get the table schema now that we know it exists
const columns = await connector.getTableSchema(tableName, schemaName);
// Create a more structured response
const formattedColumns = columns.map((col) => ({
name: col.column_name,
type: col.data_type,
nullable: col.is_nullable === "YES",
default: col.column_default,
}));
// Prepare response data
const responseData = {
table: tableName,
schema: schemaName,
columns: formattedColumns,
count: formattedColumns.length,
};
// Use the utility to create a standardized response
return createResourceSuccessResponse(uri.href, responseData);
} catch (error) {
// Handle any other errors that might occur
return createResourceErrorResponse(
uri.href,
`Error retrieving schema: ${(error as Error).message}`,
"SCHEMA_RETRIEVAL_ERROR"
);
}
}
