refactor: to node action (#47)

Refactoring the action from a composite to Node action. This change improves security through pinning of packages as well as better test-ability and error handling.

Reviewed-on: #47
Co-authored-by: Timo Behrendt <t.behrendt@t00n.de>
Co-committed-by: Timo Behrendt <t.behrendt@t00n.de>

src/index.ts

@@ -0,0 +1,3 @@
+import { run } from "./main";
+
+run();

src/main.ts

@@ -0,0 +1,18 @@
+import * as core from "@actions/core";
+import { readFileSync } from "node:fs";
+import { validateJson } from "./validation";
+
+export async function run(): Promise<void> {
+  try {
+    const jsonFilePath = core.getInput("json-file");
+    core.info(`Validating JSON file: ${jsonFilePath}`);
+
+    const json = readFileSync(jsonFilePath, "utf8");
+
+    await validateJson(json);
+
+    core.info("JSON file is valid");
+  } catch (error) {
+    core.setFailed(`Error validating JSON file: ${error}`);
+  }
+}

src/validation.test.ts

@@ -0,0 +1,109 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { validateJson } from "./validation";
+
+global.fetch = vi.fn();
+
+const validSchema = JSON.stringify({
+  $id: "https://t00n.de/schema.json",
+  title:
+    "JSON schema for Renovate 43.244.4 config files (https://renovatebot.com/)",
+  $schema: "http://json-schema.org/draft-07/schema#",
+  type: "object",
+  properties: {
+    $schema: {
+      type: "string",
+    },
+    name: {
+      type: "string",
+    },
+  },
+  required: ["name"],
+  additionalProperties: false,
+});
+
+describe("validateJson()", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("throws an error if the JSON file is not valid JSON", async () => {
+    const jsonFile = {
+      despiteThisBeingValidJson: "toString() breaks it, making it invalid",
+    }.toString();
+    await expect(validateJson(jsonFile)).rejects.toThrow(
+      '"[object Object]" is not valid JSON',
+    );
+  });
+
+  it("throws an error if the JSON file does not contain a $schema property", async () => {
+    const jsonFile = JSON.stringify({
+      validJson: true,
+    });
+    await expect(validateJson(jsonFile)).rejects.toThrow(
+      "No schema found in JSON file.",
+    );
+  });
+
+  it("throws an error if the schema cannot be fetched", async () => {
+    vi.mocked(fetch).mockRejectedValue(new Error("Failed to fetch schema"));
+    const jsonFile = JSON.stringify({ $schema: "http://t00n.de/404.json" });
+    await expect(validateJson(jsonFile)).rejects.toThrow(
+      "Failed to fetch schema",
+    );
+  });
+
+  it("throws an error if the schema file is not valid", async () => {
+    vi.mocked(fetch).mockResolvedValue(
+      // @ts-expect-error - mock response
+      {
+        ok: true,
+        text: async () =>
+          ({
+            despiteThisBeingValidJson:
+              "toString() breaks it, making it invalid",
+          }).toString(),
+      },
+    );
+
+    const jsonFile = JSON.stringify({
+      $schema: "https://json-schema.org/draft-07/schema",
+    });
+    await expect(validateJson(jsonFile)).rejects.toThrow(
+      '"[object Object]" is not valid JSON',
+    );
+  });
+
+  it("throws an error if the JSON file does not match the schema", async () => {
+    vi.mocked(fetch).mockResolvedValue(
+      // @ts-expect-error - mock response
+      {
+        ok: true,
+        text: async () => validSchema,
+      },
+    );
+
+    const jsonFile = JSON.stringify({
+      $schema: "https://json-schema.org/draft-07/schema",
+      notTheExpectedField: 42,
+    });
+    await expect(validateJson(jsonFile)).rejects.toThrow(
+      "JSON file is not valid: No errors",
+    );
+  });
+
+  it("does not throw an error if the JSON file is valid", async () => {
+    vi.mocked(fetch).mockResolvedValue(
+      // @ts-expect-error - mock response
+      {
+        ok: true,
+        text: async () => validSchema,
+      },
+    );
+
+    const jsonFile = JSON.stringify({
+      $schema: "https://t00n.de/schema.json",
+      name: "John Doe",
+    });
+    await expect(validateJson(jsonFile)).resolves.toBeUndefined();
+  });
+});

src/validation.ts

@@ -0,0 +1,25 @@
+import Ajv from "ajv";
+
+export const validateJson = async (jsonFileContent: string): Promise<void> => {
+  const jsonObject = JSON.parse(jsonFileContent);
+
+  const schema = jsonObject["$schema"];
+  if (!schema) {
+    throw new Error("No schema found in JSON file.");
+  }
+
+  const schemaUrl = new URL(schema);
+
+  const schemaContent = await fetch(schemaUrl.toString());
+  const schemaText = await schemaContent.text();
+  const schemaObject = JSON.parse(schemaText);
+
+  const validator = new Ajv({
+    strict: false,
+  });
+  const validate = validator.compile(schemaObject);
+  const isValid = validate(jsonObject);
+  if (!isValid) {
+    throw new Error(`JSON file is not valid: ${validator.errorsText()}`);
+  }
+};