# Utils The `@aziontech/utils` package is the Azion Lib library of helpers for functions. Two of its functions answer a request with a static file of a single-page application (SPA) or a multi-page application (MPA), and the third turns an incoming request into a plain object. The functions make no API calls, need no token, and return their result directly. Install the package: ```bash npm install @aziontech/utils ``` Import the functions from `@aziontech/utils/edge`. The package root exports only two objects, `edge` and `node`, so `import { mountSPA } from '@aziontech/utils'` fails with a `SyntaxError`. This page does not document the `node` entry, `@aziontech/utils/node`. `mountSPA` and `mountMPA` do not run in Node.js, where they fail with `TypeError: fetch failed`, so their samples run inside a function. `parseRequest` runs in Node.js and inside a function. The function samples on this page are JavaScript modules served locally with [azion dev](/en/documentation/devtools/cli/dev-command/), and the Node.js sample is a TypeScript ES module that uses top-level `await`. --- ## Static files in the build `mountSPA` and `mountMPA` read files through `file:///` URLs. Inside a function, these URLs resolve to the files that the `build.memoryFS` setting of [azion.config.js](/en/documentation/devtools/cli/azion-config-js/#build) embeds in the build. A file that the build does not embed cannot be served. The samples on this page use a project whose `data/` folder holds `index.html`, `about/index.html`, and `hello.txt`. Add this `build` block to the object that `azion.config.mjs` exports, so the build embeds `data/`: ```javascript build: { memoryFS: { injectionDirs: ['./data'], removePathPrefix: './data', }, }, ``` `injectionDirs` names the folders the build embeds. `removePathPrefix` removes the folder name from each file path, so `data/index.html` is read at `file:///index.html`. With `removePathPrefix: './'`, the same file is read at `file:///data/index.html` instead, and the `mount*` functions do not find it. --- ## mountSPA Answers a request to a single-page application with a file from the build. A path without a file extension, such as `/dashboard/settings`, returns `index.html`. A path with an extension, such as `/hello.txt`, returns that file. ```typescript function mountSPA(requestURL: string): Promise; ``` | Parameter | Type | Required | Description | | ------------ | -------- | -------- | ----------------------------------------------- | | `requestURL` | `string` | Yes | The URL of the incoming request, `request.url`. | Returns a `Response` that holds the file. When the build has no file for the path, the call throws an error, `Error: ENOENT: no such file or directory`, and the function answers with status 500 and an empty body. This function answers every request with `mountSPA` and logs the path and the status: ```javascript import { mountSPA } from '@aziontech/utils/edge'; export default { async fetch(request) { // Routes without a file extension get index.html; assets are fetched as they are const myApp = await mountSPA(request.url); console.log('mountSPA', new URL(request.url).pathname, '->', myApp.status); return myApp; }, }; ``` Served locally with `azion dev`, the root, a route, a file, and a missing file return: ```text $ curl http://localhost:3333/ HTTP/1.1 200 OK content-type: text/html

index

$ curl http://localhost:3333/dashboard/settings HTTP/1.1 200 OK content-type: text/html

index

$ curl http://localhost:3333/hello.txt HTTP/1.1 200 OK content-type: text/plain Hello from memoryFS $ curl http://localhost:3333/missing.css HTTP/1.1 500 Internal Server Error Content-Length: 0 ``` The function logs the status of each request it answers, then the error that the missing file raises: ```text mountSPA / -> 200 mountSPA /dashboard/settings -> 200 mountSPA /hello.txt -> 200 Error: ENOENT: no such file or directory, open '/.edge/storage/missing.css' ``` --- ## mountMPA Answers a request to a multi-page application with a file from the build. A path without a file extension returns the `index.html` of the folder that the path names: `/about` and `/about/` both return `about/index.html`, and `/` returns `index.html`. A path with an extension, such as `/hello.txt`, returns that file. ```typescript function mountMPA(requestURL: string): Promise; ``` | Parameter | Type | Required | Description | | ------------ | -------- | -------- | ----------------------------------------------- | | `requestURL` | `string` | Yes | The URL of the incoming request, `request.url`. | Returns a `Response` that holds the file. This function answers every request with `mountMPA` and logs the path and the status: ```javascript import { mountMPA } from '@aziontech/utils/edge'; export default { async fetch(request) { // /about is served from about/index.html const myApp = await mountMPA(request.url); console.log('mountMPA', new URL(request.url).pathname, '->', myApp.status); return myApp; }, }; ``` Served locally with `azion dev`, the root, a page with and without a trailing slash, and a file return: ```text $ curl http://localhost:3333/ HTTP/1.1 200 OK content-type: text/html

index

$ curl http://localhost:3333/about HTTP/1.1 200 OK content-type: text/html

about

$ curl http://localhost:3333/about/ HTTP/1.1 200 OK content-type: text/html

about

$ curl http://localhost:3333/hello.txt HTTP/1.1 200 OK content-type: text/plain Hello from memoryFS ``` --- ## parseRequest Reads an incoming request and returns its method, URL parts, headers, cookies, body, and client data as one plain object. ```typescript function parseRequest(request: AzionRuntimeRequest): Promise; ``` | Parameter | Type | Required | Description | | --------- | --------------------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | | `request` | `AzionRuntimeRequest` | Yes | The incoming request. Pass the request itself, not the fetch event. The type comes from the [Types](/en/documentation/devtools/azion-lib/types/) package. | Returns the parsed request. The package declares the `ParsedRequest` type but does not export it, so let TypeScript infer the type of the result. The result holds these properties: | Property | Type | Description | | ------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------- | ------------------------------------------------------------------------------------------------------ | | `timestamp` | `string` | The time of the call, in ISO 8601 format. | | `method` | `string` | The HTTP method. | | `url` | `object` | The URL parts: `full`, `protocol`, `hostname`, `path`, and `query`, an object of the query parameters. | | `headers` | `Record` | Every request header, with lowercase names. | | `cookies` | `Record` | The cookies of the `Cookie` header, by name. | | `body` | `string \| null` | The request body as text. | | `client` | `object` | `ip`, the client IP address, and `userAgent`, the `User-Agent` header. | | `referer`, `origin`, `cacheControl`, `pragma`, `contentType`, `contentLength`, `acceptLanguage`, `acceptEncoding`, `priority`, `host` | `string` | The value of the matching request header, or `Unknown` when the request does not carry it. | | `authorization` | `string` | `Not Present` when the request has no `Authorization` header. | | `metadata` | `AzionRuntimeRequestMetadata` | Declared by the type. The result of a local call has no `metadata` key. | The TypeScript sample imports `AzionRuntimeRequest` from `@aziontech/types`, so install that package too with `npm install @aziontech/types`. This sample builds a `POST` request by hand and prints four properties of the result: ```typescript import { parseRequest } from '@aziontech/utils/edge'; import type { AzionRuntimeRequest } from '@aziontech/types'; // In a function, pass the incoming request; here one is built by hand const request = new Request('https://example.com/products?id=42', { method: 'POST', headers: { 'Content-Type': 'application/json', Cookie: 'session=abc123', 'User-Agent': 'docs-sample' }, body: JSON.stringify({ qty: 1 }), }) as AzionRuntimeRequest; const parsedRequest = await parseRequest(request); console.log(parsedRequest.method, parsedRequest.url, parsedRequest.cookies, parsedRequest.body); ``` Output: ```text POST { full: 'https://example.com/products?id=42', protocol: 'https:', hostname: 'example.com', path: '/products', query: { id: '42' } } { session: 'abc123' } {"qty":1} ``` Inside a function, pass the incoming request. This function returns the whole result as JSON: ```javascript import { parseRequest } from '@aziontech/utils/edge'; export default { async fetch(request) { const parsedRequest = await parseRequest(request); return new Response(JSON.stringify(parsedRequest, null, 2), { headers: { 'content-type': 'application/json' } }); }, }; ``` Served locally with `azion dev`, a `POST` request with a cookie and a JSON body returns the result below. Locally, `client.ip` is `Unknown` and the result has no `metadata` key, because the local runtime has no `request.metadata`. ```text $ curl -X POST -H 'Content-Type: application/json' -H 'Cookie: session=abc123' -d '{"qty":1}' 'http://localhost:3333/products?id=42' HTTP/1.1 200 OK content-type: application/json { "timestamp": "2026-01-01T12:00:00.000Z", "method": "POST", "url": { "full": "http://localhost:3333/products?id=42", "protocol": "http:", "hostname": "localhost", "path": "/products", "query": { "id": "42" } }, "headers": { "accept": "*/*", "content-length": "9", "content-type": "application/json", "cookie": "session=abc123", "host": "localhost:3333", "user-agent": "curl/8.7.1" }, "cookies": { "session": "abc123" }, "body": "{\"qty\":1}", "client": { "ip": "Unknown", "userAgent": "curl/8.7.1" }, "referer": "Unknown", "origin": "Unknown", "cacheControl": "Unknown", "pragma": "Unknown", "contentType": "application/json", "contentLength": "9", "acceptLanguage": "Unknown", "acceptEncoding": "Unknown", "priority": "Unknown", "host": "localhost:3333", "authorization": "Not Present" } ``` --- ## Related resources - [Azion Lib](/en/documentation/devtools/azion-lib.md): The libraries Azion Lib ships and the package that carries each one. - [How Azion Lib works](/en/documentation/devtools/azion-lib/how-it-works.md): Which Azion Lib modules run in Node.js, which run inside a function, and why. - [azion.config.js](/en/documentation/devtools/cli/azion-config-js.md): The build settings, memoryFS among them, that decide which files a function can serve. - [Azion CLI dev](/en/documentation/devtools/cli/dev-command.md): Serve a function locally and test the files and requests it handles.