setRules endpoint for Storage Emulator (firebase#3332)

Author: samtstern

src/emulator/storage/index.ts

@@ -7,7 +7,7 @@ import { StorageLayer } from "./files";
 import * as chokidar from "chokidar";
 import { EmulatorLogger } from "../emulatorLogger";
 import * as fs from "fs";
-import { StorageRulesetInstance, StorageRulesRuntime } from "./rules/runtime";
+import { StorageRulesetInstance, StorageRulesRuntime, StorageRulesIssues } from "./rules/runtime";
 import { Source } from "./rules/types";
 import { FirebaseError } from "../../error";
 import { getDownloadDetails } from "../downloadableEmulators";
@@ -104,10 +104,17 @@ export class StorageEmulator implements EmulatorInstance {
     };
   }
 
-  private async loadRuleset(): Promise<void> {
+  public async loadRuleset(source?: Source): Promise<StorageRulesIssues> {
+    if (source) {
+      this._rulesetSource = source;
+    }
+
     if (!this._rulesetSource) {
-      this._logger.log("WARN", "Attempting to update ruleset without a source.");
-      return;
+      const msg = "Attempting to update ruleset without a source.";
+      this._logger.log("WARN", msg);
+
+      const error = JSON.stringify({ error: msg });
+      return new StorageRulesIssues([error], []);
     }
 
     const { ruleset, issues } = await this._rulesRuntime.loadRuleset(this._rulesetSource);
@@ -137,6 +144,8 @@ export class StorageEmulator implements EmulatorInstance {
     } else {
       this._rules = ruleset;
     }
+
+    return issues;
   }
 
   async connect(): Promise<void> {

src/emulator/storage/server.ts

@@ -73,6 +73,46 @@ export function createApp(
     res.sendStatus(200);
   });
 
+  app.put("/internal/setRules", async (req, res) => {
+    // Payload:
+    // {
+    //   rules: {
+    //     files: [{ name:<string> content: <string> }]
+    //   }
+    // }
+    // TODO: Add a bucket parameter for per-bucket rules support
+
+    const rules = req.body.rules;
+    if (!(rules && Array.isArray(rules.files) && rules.files.length > 0)) {
+      res.status(400).send("Request body must include 'rules.files' array .");
+      return;
+    }
+
+    const file = rules.files[0];
+    if (!(file.name && file.content)) {
+      res
+        .status(400)
+        .send(
+          "Request body must include 'rules.files' array where each member contains 'name' and 'content'."
+        );
+      return;
+    }
+
+    const name = file.name;
+    const content = file.content;
+    const issues = await emulator.loadRuleset({ files: [{ name, content }] });
+
+    if (issues.errors.length > 0) {
+      res.status(400).json({
+        message: "There was an error updating rules, see logs for more details",
+      });
+    }
+
+    res.sendStatus(200).json({
+      message: "Rules updated successfully",
+    });
+  });
+
   app.post("/internal/reset", (req, res) => {
     storageLayer.reset();
     res.sendStatus(200);