adds feature to prevent GPT-4 model selection (default off)

src/config.ts

@@ -119,6 +119,11 @@ type Config = {
    * Desination URL to redirect blocked requests to, for non-JSON requests.
    */
   blockRedirect?: string;
+  /**
+   * Whether the proxy should disallow requests for GPT-4 models in order to
+   * prevent excessive spend.  Applies only to OpenAI.
+   */
+  turboOnly?: boolean;
 };
 
 // To change configs, create a file called .env in the root directory.
@@ -162,6 +167,7 @@ export const config: Config = {
     "You must be over the age of majority in your country to use this service."
   ),
   blockRedirect: getEnvWithDefault("BLOCK_REDIRECT", "https://www.9gag.com"),
+  turboOnly: getEnvWithDefault("TURBO_ONLY", false),
 } as const;
 
 function migrateConfigs() {

src/info-page.ts

@@ -89,7 +89,7 @@ type ServiceInfo = {
 function getOpenAIInfo() {
   const info: { [model: string]: Partial<ServiceInfo> } = {};
   const keys = keyPool.list().filter((k) => k.service === "openai");
-  const hasGpt4 = keys.some((k) => k.isGpt4);
+  const hasGpt4 = keys.some((k) => k.isGpt4) && !config.turboOnly;
 
   if (keyPool.anyUnchecked()) {
     const uncheckedKeys = keys.filter((k) => !k.lastChecked);
@@ -197,7 +197,7 @@ Logs are anonymous and do not contain IP addresses or timestamps. [You can see t
       const turboWait = getQueueInformation("turbo").estimatedQueueTime;
       const gpt4Wait = getQueueInformation("gpt-4").estimatedQueueTime;
       waits.push(`**Turbo:** ${turboWait}`);
-      if (keyPool.list().some((k) => k.isGpt4)) {
+      if (keyPool.list().some((k) => k.isGpt4) && !config.turboOnly) {
         waits.push(`**GPT-4:** ${gpt4Wait}`);
       }
     }

src/key-management/openai/provider.ts

@@ -128,11 +128,17 @@ export class OpenAIKeyProvider implements KeyProvider<OpenAIKey> {
     );
     if (availableKeys.length === 0) {
       let message = needGpt4
-        ? "No GPT-4 keys available.  Try selecting a non-GPT-4 model."
+        ? "No GPT-4 keys available.  Try selecting a Turbo model."
         : "No active OpenAI keys available.";
       throw new Error(message);
     }
 
+    if (needGpt4 && config.turboOnly) {
+      throw new Error(
+        "Proxy operator has disabled GPT-4 to reduce quota usage.  Try selecting a Turbo model."
+      );
+    }
+
     // Select a key, from highest priority to lowest priority:
     // 1. Keys which are not rate limited
     //    a. We ignore rate limits from over a minute ago