feat: adds exported-data resource

Author: himanshusinghs

src/resources/common/exported-data.ts

@@ -0,0 +1,114 @@
+import {
+    CompleteResourceTemplateCallback,
+    ListResourcesCallback,
+    ReadResourceTemplateCallback,
+    ResourceTemplate,
+} from "@modelcontextprotocol/sdk/server/mcp.js";
+import { Server } from "../../server.js";
+
+export class ExportedData {
+    private readonly name = "exported-data";
+    private readonly description = "Data files exported in the current session.";
+    private readonly uri = "exported-data://{exportName}";
+
+    constructor(private readonly server: Server) {
+        this.server.session.on("export-available", (uri) => {
+            this.server.mcpServer.sendResourceListChanged();
+            void this.server.mcpServer.server.sendResourceUpdated({
+                uri,
+            });
+            this.server.mcpServer.sendResourceListChanged();
+        });
+        this.server.session.on("export-expired", () => {
+            this.server.mcpServer.sendResourceListChanged();
+        });
+    }
+
+    public register(): void {
+        this.server.mcpServer.registerResource(
+            this.name,
+            new ResourceTemplate(this.uri, {
+                /**
+                 * A few clients have the capability of listing templated
+                 * resources as well and this callback provides support for that
+                 * */
+                list: this.listResourcesCallback,
+                /**
+                 * This is to provide auto completion when user starts typing in
+                 * value for template variable, in our case, exportName */
+                complete: {
+                    exportName: this.autoCompleteExportName,
+                },
+            }),
+            { description: this.description },
+            this.readResourceCallback
+        );
+    }
+
+    private listResourcesCallback: ListResourcesCallback = () => {
+        const sessionId = this.server.session.sessionId;
+        if (!sessionId) {
+            // Note that we don't throw error here because this is a
+            // non-critical path and safe to return the most harmless value.
+
+            // TODO: log warn here
+            return { resources: [] };
+        }
+
+        const sessionExports = this.server.exportsManager.listAvailableExports();
+        return {
+            resources: sessionExports.map(({ name, uri }) => ({
+                name: name,
+                description: this.exportNameToDescription(name),
+                uri: uri,
+                mimeType: "application/json",
+            })),
+        };
+    };
+
+    private autoCompleteExportName: CompleteResourceTemplateCallback = (value) => {
+        const sessionId = this.server.session.sessionId;
+        if (!sessionId) {
+            // Note that we don't throw error here because this is a
+            // non-critical path and safe to return the most harmless value.
+
+            // TODO: log warn here
+            return [];
+        }
+
+        const sessionExports = this.server.exportsManager.listAvailableExports();
+        return sessionExports.filter(({ name }) => name.startsWith(value)).map(({ name }) => name);
+    };
+
+    private readResourceCallback: ReadResourceTemplateCallback = async (uri, { exportName }) => {
+        const sessionId = this.server.session.sessionId;
+        if (!sessionId) {
+            throw new Error("Cannot retrieve exported data, session is not valid.");
+        }
+
+        if (typeof exportName !== "string") {
+            throw new Error("Cannot retrieve exported data, exportName not provided.");
+        }
+
+        return {
+            contents: [
+                {
+                    uri: this.server.exportsManager.exportNameToResourceURI(exportName),
+                    text: await this.server.exportsManager.readExport(exportName),
+                    mimeType: "application/json",
+                },
+            ],
+        };
+    };
+
+    private exportNameToDescription(exportName: string) {
+        const match = exportName.match(/^(.+)\.(\d+)\.json$/);
+        if (!match) return "Exported data for an unknown namespace.";
+
+        const [, namespace, timestamp] = match;
+        if (!namespace || !timestamp) {
+            return "Exported data for an unknown namespace.";
+        }
+        return `Export from ${namespace} done on ${new Date(parseInt(timestamp)).toISOString()}`;
+    }
+}

src/resources/resources.ts

@@ -1,4 +1,5 @@
 import { ConfigResource } from "./common/config.js";
 import { DebugResource } from "./common/debug.js";
+import { ExportedData } from "./common/exported-data.js";
 
-export const Resources = [ConfigResource, DebugResource] as const;
+export const Resources = [ConfigResource, DebugResource, ExportedData] as const;