skip Positron Proxy for fastapi and streamlit apps on PWB (#5138)

- addresses: #5027 and #5026 - skip the Positron Proxy when running fastapi and streamlit apps in Positron on Workbench - add log output channel for Positron Proxy for easier debugging - add typescript dev dependency to Positron Run App package.json to make `vsce package` available for that extension ### QA Notes I've been testing with the apps from https://github.com/posit-dev/qa-example-content/tree/main/workspaces/python_apps. - Positron on Workbench (Linux Ubuntu x86_64): Dash, Fastapi, Flask, Gradio, Streamlit all good ✅ - Note that I sometimes have to refresh the Viewer for the Fastapi app before it works, as the app may be opened in the Viewer before the app is actually ready - Positron Server Web (Mac): Dash, Fastapi, Flask, Gradio, Streamlit all good ✅ - Positron Desktop (Mac): Dash, Fastapi, Flask, Gradio, Streamlit all good ✅ --------- Co-authored-by: sharon wang <[email protected]>
posit-dev · Oct 29, 2024 · a896e6e · a896e6e
1 parent c6a9d79
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diff --git a/extensions/positron-proxy/src/extension.ts b/extensions/positron-proxy/src/extension.ts
@@ -12,6 +12,11 @@ import { PositronProxy } from './positronProxy';
  */
 export type ProxyServerStyles = { readonly [key: string]: string | number };
 
+/**
+ * Positron Proxy log output channel.
+ */
+export const log = vscode.window.createOutputChannel('Positron Proxy', { log: true });
+
 /**
  * Activates the extension.
  * @param context An ExtensionContext that contains the extention context.
@@ -20,6 +25,9 @@ export function activate(context: vscode.ExtensionContext) {
 	// Create the PositronProxy object.
 	const positronProxy = new PositronProxy(context);
 
+	// Create the log output channel.
+	context.subscriptions.push(log);
+
 	// Register the positronProxy.startHelpProxyServer command and add its disposable.
 	context.subscriptions.push(
 		vscode.commands.registerCommand(

diff --git a/extensions/positron-proxy/src/positronProxy.ts b/extensions/positron-proxy/src/positronProxy.ts
@@ -8,7 +8,8 @@ import fs = require('fs');
 import path = require('path');
 import express from 'express';
 import { AddressInfo, Server } from 'net';
-import { ProxyServerStyles } from './extension';
+import { log, ProxyServerStyles } from './extension';
+// eslint-disable-next-line no-duplicate-imports
 import { Disposable, ExtensionContext } from 'vscode';
 import { createProxyMiddleware, responseInterceptor } from 'http-proxy-middleware';
 import { HtmlProxyServer } from './htmlProxy';
@@ -176,7 +177,7 @@ export class PositronProxy implements Disposable {
 				this._helpStyleOverrides !== undefined &&
 				this._helpScript !== undefined;
 		} catch (error) {
-			console.log(`Failed to load the resources/scripts_help.html file.`);
+			log.error(`Failed to load the resources/scripts_help.html file: ${JSON.stringify(error)}`);
 		}
 	}
 
@@ -202,6 +203,8 @@ export class PositronProxy implements Disposable {
 	 * @returns The server origin.
 	 */
 	startHelpProxyServer(targetOrigin: string): Promise<string> {
+		log.debug(`Starting a help proxy server for target: ${targetOrigin}...`);
+
 		// Start the proxy server.
 		return this.startProxyServer(
 			targetOrigin,
@@ -257,6 +260,8 @@ export class PositronProxy implements Disposable {
 	 * stopped.
 	 */
 	stopProxyServer(targetOrigin: string): boolean {
+		log.debug(`Stopping proxy server for target: ${targetOrigin}...`);
+
 		// See if we have a proxy server for the target origin. If we do, stop it.
 		const proxyServer = this._proxyServers.get(targetOrigin);
 		if (proxyServer) {
@@ -278,6 +283,8 @@ export class PositronProxy implements Disposable {
 	 * @returns The server URL.
 	 */
 	async startHtmlProxyServer(targetPath: string) {
+		log.debug(`Starting an HTML proxy server for target: ${targetPath}...`);
+
 		if (!this._htmlProxyServer) {
 			this._htmlProxyServer = new HtmlProxyServer();
 		}
@@ -299,6 +306,7 @@ export class PositronProxy implements Disposable {
 	 * @returns The server origin.
 	 */
 	startHttpProxyServer(targetOrigin: string): Promise<string> {
+		log.debug(`Starting an HTTP proxy server for target: ${targetOrigin}...`);
 		// Start the proxy server.
 		return this.startProxyServer(targetOrigin, htmlContentRewriter);
 	}
@@ -312,6 +320,7 @@ export class PositronProxy implements Disposable {
 	 * @returns The pending proxy server info.
 	 */
 	startPendingHttpProxyServer(): Promise<PendingProxyServer> {
+		log.debug('Starting a pending HTTP proxy server...');
 		// Start the proxy server and return the pending proxy server info. The caller will need to
 		// call finishProxySetup to complete the proxy setup.
 		return this.startNewProxyServer(htmlContentRewriter);
@@ -332,7 +341,7 @@ export class PositronProxy implements Disposable {
 		// server origin.
 		const proxyServer = this._proxyServers.get(targetOrigin);
 		if (proxyServer) {
-			console.debug(`Existing proxy server ${proxyServer.serverOrigin} found for target: ${targetOrigin}.`);
+			log.debug(`Existing proxy server ${proxyServer.serverOrigin} found for target: ${targetOrigin}.`);
 			return proxyServer.serverOrigin;
 		}
 
@@ -341,20 +350,21 @@ export class PositronProxy implements Disposable {
 			// We don't have an existing proxy server for the target origin, so start a new one.
 			pendingProxy = await this.startNewProxyServer(contentRewriter);
 		} catch (error) {
-			console.error(`Failed to start a proxy server for ${targetOrigin}.`);
+			log.error(`Failed to start a proxy server for ${targetOrigin}: ${JSON.stringify(error)}`);
 			throw error;
 		}
 
+		const externalUri = pendingProxy.externalUri.toString(true);
 		try {
 			// Finish setting up the proxy server.
 			await pendingProxy.finishProxySetup(targetOrigin);
 		} catch (error) {
-			console.error(`Failed to finish setting up the proxy server at ${pendingProxy.externalUri} for target: ${targetOrigin}.`);
+			log.error(`Failed to finish setting up the proxy server at ${externalUri} for target ${targetOrigin}: ${JSON.stringify(error)}`);
 			throw error;
 		}
 
 		// Return the external URI.
-		return pendingProxy.externalUri.toString();
+		return externalUri;
 	}
 
 	/**
@@ -377,8 +387,10 @@ export class PositronProxy implements Disposable {
 
 		// Ensure the address is an AddressInfo.
 		if (!isAddressInfo(address)) {
+			const error = `Failed to get the address info ${JSON.stringify(address)} for the server.`;
+			log.error(error);
 			server.close();
-			throw new Error(`Failed to get the address info ${JSON.stringify(address)} for the server.`);
+			throw new Error(error);
 		}
 
 		// Create the server origin.
@@ -388,6 +400,8 @@ export class PositronProxy implements Disposable {
 		const originUri = vscode.Uri.parse(serverOrigin);
 		const externalUri = await vscode.env.asExternalUri(originUri);
 
+		log.debug(`Started proxy server at ${serverOrigin} for external URI ${externalUri.toString(true)}.`);
+
 		// Return the pending proxy info.
 		return {
 			externalUri: externalUri,
@@ -423,6 +437,11 @@ export class PositronProxy implements Disposable {
 		app: express.Express,
 		contentRewriter: ContentRewriter
 	) {
+		log.debug(`Finishing proxy server setup for target ${targetOrigin}\n` +
+			`\tserverOrigin: ${serverOrigin}\n` +
+			`\texternalUri: ${externalUri.toString(true)}`
+		);
+
 		// Add the proxy server.
 		this._proxyServers.set(targetOrigin, new ProxyServer(
 			serverOrigin,
@@ -436,16 +455,30 @@ export class PositronProxy implements Disposable {
 			changeOrigin: true,
 			selfHandleResponse: true,
 			ws: true,
-			// Logging for development work.
-			// onProxyReq: (proxyReq, req, res, options) => {
-			// 	console.log(`Proxy request ${serverOrigin}${req.url} -> ${targetOrigin}${req.url}`);
-			// },
+			onProxyReq: (proxyReq, req, _res, _options) => {
+				log.trace(`onProxyReq - proxy request ${serverOrigin}${req.url} -> ${targetOrigin}${req.url}` +
+					`\n\tmethod: ${proxyReq.method}` +
+					`\n\tprotocol: ${proxyReq.protocol}` +
+					`\n\thost: ${proxyReq.host}` +
+					`\n\turl: ${proxyReq.path}` +
+					`\n\theaders: ${JSON.stringify(proxyReq.getHeaders())}` +
+					`\n\texternal uri: ${externalUri.toString(true)}`
+				);
+			},
 			onProxyRes: responseInterceptor(async (responseBuffer, proxyRes, req, _res) => {
+				log.trace(`onProxyRes - proxy response ${targetOrigin}${req.url} -> ${serverOrigin}${req.url}` +
+					`\n\tstatus: ${proxyRes.statusCode}` +
+					`\n\tstatusMessage: ${proxyRes.statusMessage}` +
+					`\n\theaders: ${JSON.stringify(proxyRes.headers)}` +
+					`\n\texternal uri: ${externalUri.toString(true)}`
+				);
+
 				// Get the URL and the content type. These must be present to call the
 				// content rewriter. Also, the scripts must be loaded.
 				const url = req.url;
 				const contentType = proxyRes.headers['content-type'];
 				if (!url || !contentType || !this._scriptsFileLoaded) {
+					log.trace(`onProxyRes - skipping response processing for ${serverOrigin}${url}`);
 					// Don't process the response.
 					return responseBuffer;
 				}

diff --git a/extensions/positron-run-app/package.json b/extensions/positron-run-app/package.json
@@ -39,7 +39,8 @@
     "@types/mocha": "^10.0.8",
     "@types/node": "^22.5.4",
     "@types/sinon": "^17.0.3",
-    "@types/sinon-test": "^2.4.6"
+    "@types/sinon-test": "^2.4.6",
+    "typescript": "^4.5.5"
   },
   "repository": {
     "type": "git",

diff --git a/extensions/positron-run-app/src/api.ts b/extensions/positron-run-app/src/api.ts
@@ -14,6 +14,9 @@ import { raceTimeout, removeAnsiEscapeCodes, SequencerByKey } from './utils';
 // Regex to match a URL with the format http://localhost:1234/path
 const localUrlRegex = /http:\/\/(localhost|127\.0\.0\.1):(\d{1,5})(\/[^\s]*)?/;
 
+const isPositronWeb = vscode.env.uiKind === vscode.UIKind.Web;
+const isRunningOnPwb = !!process.env.RS_SERVER_URL && isPositronWeb;
+
 type PositronProxyInfo = {
 	proxyPath: string;
 	externalUri: vscode.Uri;
@@ -88,12 +91,18 @@ export class PositronRunAppApiImpl implements PositronRunApp, vscode.Disposable
 			return;
 		}
 
+		// Set up the proxy server for the application if applicable.
+		let urlPrefix = undefined;
+		let proxyInfo: PositronProxyInfo | undefined;
+		if (shouldUsePositronProxy(options.name)) {
+			// Start the proxy server
+			proxyInfo = await vscode.commands.executeCommand<PositronProxyInfo>('positronProxy.startPendingProxyServer');
+			log.debug(`Proxy started for app at proxy path ${proxyInfo.proxyPath} with uri ${proxyInfo.externalUri.toString()}`);
+			urlPrefix = proxyInfo.proxyPath;
+		}
+
 		// Get the terminal options for the application.
 		progress.report({ message: vscode.l10n.t('Getting terminal options...') });
-		// Start the proxy server
-		const proxyInfo = await vscode.commands.executeCommand<PositronProxyInfo>('positronProxy.startPendingProxyServer');
-		log.debug(`Proxy started for app at proxy path ${proxyInfo.proxyPath} with uri ${proxyInfo.externalUri.toString()}`);
-		const urlPrefix = proxyInfo.proxyPath;
 		const terminalOptions = await options.getTerminalOptions(runtime, document, urlPrefix);
 		if (!terminalOptions) {
 			return;
@@ -221,11 +230,18 @@ export class PositronRunAppApiImpl implements PositronRunApp, vscode.Disposable
 			return;
 		}
 
+		// Set up the proxy server for the application if applicable.
+		let urlPrefix = undefined;
+		let proxyInfo: PositronProxyInfo | undefined;
+		if (shouldUsePositronProxy(options.name)) {
+			// Start the proxy server
+			proxyInfo = await vscode.commands.executeCommand<PositronProxyInfo>('positronProxy.startPendingProxyServer');
+			log.debug(`Proxy started for app at proxy path ${proxyInfo.proxyPath} with uri ${proxyInfo.externalUri.toString()}`);
+			urlPrefix = proxyInfo.proxyPath;
+		}
+
 		// Get the debug config for the application.
 		progress.report({ message: vscode.l10n.t('Getting debug configuration...') });
-		// Start the proxy server
-		const proxyInfo = await vscode.commands.executeCommand<PositronProxyInfo>('positronProxy.startPendingProxyServer');
-		const urlPrefix = proxyInfo.proxyPath;
 		const debugConfig = await options.getDebugConfiguration(runtime, document, urlPrefix);
 		if (!debugConfig) {
 			return;
@@ -328,7 +344,7 @@ export class PositronRunAppApiImpl implements PositronRunApp, vscode.Disposable
 	}
 }
 
-async function previewUrlInExecutionOutput(execution: vscode.TerminalShellExecution, proxyInfo: PositronProxyInfo, urlPath?: string) {
+async function previewUrlInExecutionOutput(execution: vscode.TerminalShellExecution, proxyInfo?: PositronProxyInfo, urlPath?: string) {
 	// Wait for the server URL to appear in the terminal output, or a timeout.
 	const stream = execution.read();
 	const url = await raceTimeout(
@@ -353,18 +369,33 @@ async function previewUrlInExecutionOutput(execution: vscode.TerminalShellExecut
 		return false;
 	}
 
-	// Convert the url to an external URI.
+	// Example: http://localhost:8500
 	const localBaseUri = vscode.Uri.parse(url.toString());
+
+	// Example: http://localhost:8500/url/path or http://localhost:8500
 	const localUri = urlPath ?
 		vscode.Uri.joinPath(localBaseUri, urlPath) : localBaseUri;
 
-	log.debug(`Viewing app at local uri: ${localUri} with external uri ${proxyInfo.externalUri.toString()}`);
+	// Example: http://localhost:8080/proxy/5678/url/path or http://localhost:8080/proxy/5678
+	let previewUri = undefined;
+	if (proxyInfo) {
+		// On Web (specifically Positron Server Web and not PWB), we need to set up the proxy with
+		// the urlPath appended to avoid issues where the app does not set the base url of the app
+		// or the base url of referenced assets correctly.
+		const applyWebPatch = isPositronWeb && !isRunningOnPwb;
+		const targetOrigin = applyWebPatch ? localUri.toString(true) : localBaseUri.toString();
+
+		// Finish the Positron proxy setup so that proxy middleware is hooked up.
+		await proxyInfo.finishProxySetup(targetOrigin);
+		previewUri = !applyWebPatch && urlPath ? vscode.Uri.joinPath(proxyInfo.externalUri, urlPath) : proxyInfo.externalUri;
+	} else {
+		previewUri = await vscode.env.asExternalUri(localUri);
+	}
 
-	// Finish the Positron proxy setup so that proxy middleware is hooked up.
-	await proxyInfo.finishProxySetup(localUri.toString());
+	log.debug(`Viewing app at local uri: ${localUri.toString(true)} with external uri ${previewUri.toString(true)}`);
 
-	// Preview the external URI.
-	positron.window.previewUrl(proxyInfo.externalUri);
+	// Preview the app in the Viewer.
+	positron.window.previewUrl(previewUri);
 
 	return true;
 }
@@ -442,3 +473,27 @@ async function showShellIntegrationNotSupportedMessage(): Promise<void> {
 		await runAppConfig.update('showShellIntegrationNotSupportedMessage', false, vscode.ConfigurationTarget.Global);
 	}
 }
+
+/**
+ * Check if the Positron proxy should be used for the given app.
+ * Generally, we should avoid skipping the proxy unless there is a good reason to do so, as the
+ * proxy gives us the ability to intercept requests and responses to the app, which is useful for
+ * things like debugging, applying styling or fixing up urls.
+ * @param appName The name of the app; indicated in extensions/positron-python/src/client/positron/webAppCommands.ts
+ * @returns Whether to use the Positron proxy for the app.
+ */
+function shouldUsePositronProxy(appName: string) {
+	switch (appName.trim().toLowerCase()) {
+		// Streamlit apps don't work in Positron on Workbench with SSL enabled when run through the proxy.
+		case 'streamlit':
+		// FastAPI apps don't work in Positron on Workbench when run through the proxy.
+		case 'fastapi':
+			if (isRunningOnPwb) {
+				return false;
+			}
+			return true;
+		default:
+			// By default, proxy the app.
+			return true;
+	}
+}
diff --git a/extensions/positron-run-app/yarn.lock b/extensions/positron-run-app/yarn.lock
@@ -33,6 +33,11 @@
   resolved "https://registry.yarnpkg.com/@types/sinonjs__fake-timers/-/sinonjs__fake-timers-8.1.5.tgz#5fd3592ff10c1e9695d377020c033116cc2889f2"
   integrity sha512-mQkU2jY8jJEF7YHjHvsQO8+3ughTL1mcnn96igfhONmR+fUPSKIkefQYpSe8bsly2Ep7oQbn/6VG5/9/0qcArQ==
 
+typescript@^4.5.5:
+  version "4.9.5"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.9.5.tgz#095979f9bcc0d09da324d58d03ce8f8374cbe65a"
+  integrity sha512-1FXk9E2Hm+QzZQ7z+McJiHL4NW1F2EzMu9Nq9i3zAaGqibafqYwCVU6WyWAuyQRRzOlxou8xZSyXLEN8oKj24g==
+
 undici-types@~6.19.2:
   version "6.19.8"
   resolved "https://registry.yarnpkg.com/undici-types/-/undici-types-6.19.8.tgz#35111c9d1437ab83a7cdc0abae2f26d88eda0a02"