feat(data-proxy)!: add handshake method

The OPTIONS http method is no longer allowed, as we need this to be able
to reliably retrieve the data proxy info from the overlay network.

Closes: #34

README.md

@@ -114,6 +114,9 @@ The two required attributes are `path` and `upstreamUrl`. These specify how the
 }
 ```
 
+> [!IMPORTANT]
+> The `OPTIONS` method is reserved and cannot be used for a route.
+
 #### Base URL per route
 
 In addition to specifying the `baseURL` at the root level you can also specify it per `route`. The `baseURL` at the `route` level will take precedence over one at the root level.
@@ -133,8 +136,8 @@ In addition to specifying the `baseURL` at the root level you can also specify i
       "baseURL": "https://btc.data-proxy.com",
       "path": "/btc-usd",
       "upstreamUrl": "https://myapi.com/btc-usd"
-    },
-  ],
+    }
+  ]
 }
 ```
 

workspace/data-proxy-sdk/src/data-proxy.ts

@@ -33,7 +33,7 @@ export interface SignedData {
 }
 
 export class DataProxy {
-	private version = "0.1.0";
+	public version = "0.1.0";
 	public publicKey: Buffer;
 	private privateKey: Buffer;
 	public options: DataProxyOptions;

workspace/data-proxy/src/config-parser.test.ts

@@ -1,5 +1,8 @@
 import { describe, expect, it } from "bun:test";
-import { assertIsOkResult } from "@seda-protocol/utils/testing";
+import {
+	assertIsErrorResult,
+	assertIsOkResult,
+} from "@seda-protocol/utils/testing";
 import { parseConfig } from "./config-parser";
 
 describe("parseConfig", () => {
@@ -120,4 +123,34 @@ describe("parseConfig", () => {
 
 		expect(result).toBeOkResult();
 	});
+
+	it("should fail if the status endpoint uses a the same route group as the proxy", () => {
+		const result = parseConfig({
+			statusEndpoints: {
+				root: "proxy",
+			},
+			routes: [],
+		});
+
+		assertIsErrorResult(result);
+		expect(result.error).toContain("can not be the same");
+	});
+
+	it.each(["OPTIONS", ["OPTIONS", "GET"]])(
+		"should error when the OPTIONS method is used for a route",
+		(method) => {
+			const resultSingle = parseConfig({
+				routes: [
+					{
+						method,
+						path: "/:coinA/*",
+						upstreamUrl: "aaaaaa.com/{*}",
+					},
+				],
+			});
+
+			assertIsErrorResult(resultSingle);
+			expect(resultSingle.error).toContain("OPTIONS method is reserved");
+		},
+	);
 });

workspace/data-proxy/src/config-parser.ts

@@ -1,11 +1,16 @@
+import { tryParseSync } from "@seda-protocol/utils";
 import { maybe } from "@seda-protocol/utils/valibot";
 import type { HTTPMethod } from "elysia";
 import { Result } from "true-myth";
 import * as v from "valibot";
 import { DEFAULT_HTTP_METHODS, DEFAULT_PROXY_ROUTE_GROUP } from "./constants";
 import { replaceParams } from "./utils/replace-params";
 
-const HttpMethodSchema = v.union([v.string(), v.array(v.string())]);
+const NotOptionsMethod = v.pipe(
+	v.string(),
+	v.notValue("OPTIONS", "OPTIONS method is reserved"),
+);
+const HttpMethodSchema = v.union([NotOptionsMethod, v.array(NotOptionsMethod)]);
 
 const RouteSchema = v.object({
 	baseURL: maybe(v.string()),
@@ -58,7 +63,27 @@ const pathRegex = new RegExp(/{(:[^}]+)}/g, "g");
 const envVariablesRegex = new RegExp(/{(\$[^}]+)}/g, "g");
 
 export function parseConfig(input: unknown): Result<Config, string> {
-	const config = v.parse(ConfigSchema, input);
+	const configResult = tryParseSync(ConfigSchema, input);
+	if (configResult.isErr) {
+		return Result.err(
+			configResult.error
+				.map((err) => {
+					const key = err.path?.reduce((path, segment) => {
+						return path.concat(".", segment.key as string);
+					}, "");
+					return `${key}: ${err.message}`;
+				})
+				.join("\n"),
+		);
+	}
+
+	const config = configResult.value;
+
+	if (config.statusEndpoints.root === config.routeGroup) {
+		return Result.err(
+			`"statusEndpoints.root" can not be the same as "routeGroup" (value: ${DEFAULT_PROXY_ROUTE_GROUP})`,
+		);
+	}
 
 	if (config.statusEndpoints.apiKey) {
 		const statusApiSecretEnvMatches =

workspace/data-proxy/src/constants.ts

@@ -27,6 +27,5 @@ export const DEFAULT_HTTP_METHODS: HTTPMethod[] = [
 	"POST",
 	"PUT",
 	"DELETE",
-	"OPTIONS",
 	"HEAD",
 ];

workspace/data-proxy/src/proxy-server.test.ts

@@ -7,7 +7,11 @@ import {
 	it,
 } from "bun:test";
 import { Secp256k1, Secp256k1Signature, keccak256 } from "@cosmjs/crypto";
-import { DataProxy, Environment } from "@seda-protocol/data-proxy-sdk";
+import {
+	constants,
+	DataProxy,
+	Environment,
+} from "@seda-protocol/data-proxy-sdk";
 import { Maybe } from "true-myth";
 import { startProxyServer } from "./proxy-server";
 import {
@@ -252,6 +256,54 @@ describe("proxy server", () => {
 		});
 	});
 
+	describe("OPTIONS methods", () => {
+		it("should return the public key and version of the data proxy", async () => {
+			const { upstreamUrl, proxyUrl, path, port } = registerHandler(
+				"get",
+				"/test",
+				async () => {
+					return HttpResponse.json({ data: "info" });
+				},
+			);
+
+			const proxy = startProxyServer(
+				{
+					routeGroup: "",
+					statusEndpoints: {
+						root: "status",
+					},
+					baseURL: Maybe.nothing(),
+					routes: [
+						{
+							baseURL: Maybe.nothing(),
+							method: "GET",
+							path,
+							upstreamUrl,
+							forwardResponseHeaders: new Set([]),
+							headers: {},
+							jsonPath: "$.data",
+						},
+					],
+				},
+				dataProxy,
+				{
+					disableProof: true,
+					port,
+				},
+			);
+
+			const response = await fetch(proxyUrl, { method: "OPTIONS" });
+			const version = response.headers.get(
+				constants.SIGNATURE_VERSION_HEADER_KEY,
+			);
+			const publicKey = response.headers.get(constants.PUBLIC_KEY_HEADER_KEY);
+
+			expect(version).toBe("0.1.0");
+			expect(publicKey).toBe(
+				"031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f",
+			);
+		});
+	});
 	describe("status endpoints", () => {
 		it("should return the status of the proxy for <statusRoot>/health", async () => {
 			const { upstreamUrl, proxyUrl, path, port } = registerHandler(

workspace/data-proxy/src/proxy-server.ts

@@ -80,9 +80,17 @@ export function startProxyServer(
 		});
 
 		for (const route of config.routes) {
-			const routeMethods = getHttpMethods(route.method);
+			app.route("OPTIONS", route.path, () => {
+				const headers = new Headers({
+					[constants.PUBLIC_KEY_HEADER_KEY]:
+						dataProxy.publicKey.toString("hex"),
+					[constants.SIGNATURE_VERSION_HEADER_KEY]: dataProxy.version,
+				});
+				return new Response(null, { headers });
+			});
 
 			// A route can have multiple methods attach to it
+			const routeMethods = getHttpMethods(route.method);
 			for (const routeMethod of routeMethods) {
 				app.route(
 					routeMethod,