I am working on a HTML5 PWA and am looking to have a "Network First, then Cache" layout so that when a user accesses the PWA it pulls down the latest version but if they are offline it uses cache.
How would i need to amend the below code for that please?
const assets = [
"/",
"/index.html",
"/about.html",
"/assets/css/main.css",
"/images/logo.png",
"/images/logo.svg",
]
self.addEventListener("install", installEvent => {
installEvent.waitUntil(
caches.open(staticCacheName).then(cache => {
cache.addAll(assets)
})
)
})
self.addEventListener("fetch", fetchEvent => {
fetchEvent.respondWith(
caches.match(fetchEvent.request).then(res => {
return res || fetch(fetchEvent.request)
})
)
})
The cache is created, but once the PWA is saved to homepage it always uses Cache.
You're looking for the "network, then cache" pattern from the Offline Cookbook:
self.addEventListener('fetch', (event) => {
event.respondWith(async function() {
try {
return await fetch(event.request);
} catch (err) {
return caches.match(event.request);
}
}());
});
After my locally installed browsers (Edge Chromium and Google Chrome) were updated to a version with Chromium >=94 fetching large files do fail.
I tested with two implementations, Fetch and XmlHttpRequest. In both implementations the HTTP status and response are the same. In browsers with Chromium version 93 the expected response is returned. When running the same code in browsers with Chromium versie 94, i do get a HTTP 200, but response is always null
Any idea if this is a specific Chromium 94 issue ?
return new Promise((resolve, reject) => {
var url = getBaseUrl() + serviceUrl;
fetch(url,{
method: "GET",
headers: {
importance: "low"
}
}).then((response) => {
if (response.status === 200) {
response.arrayBuffer().then(buffer => resolve(buffer))
} else {
reject(response);
}
})
});
and
return new Promise((resolve, reject) => {
const xhr = new XMLHttpRequest();
var url = getBaseUrl() + serviceUrl;
xhr.open('GET', url, true);
xhr.responseType = 'arraybuffer';
xhr.onload = function () {
if (this.status === 200) {
resolve(this.response);
} else {
reject(this.response);
}
};
xhr.send();
});
I'm trying to create a Puppeteer function in GCP which can be triggered by Pub/Sub messages. The function is callable, but doesn't behave as expected and throws a Timeout Error once browser tries to initialize. Could the trigger possibly be using a NodeJS environment different from HTTP trigger?
I'm also very new to NodeJS, so I apologize ahead of time if the issue is blatantly obvious.
I've created an HTTP trigger for the function which behaves as expected. I copy/paste the Puppeteer Function below into the index.js when creating the Cloud Function, but separated in example for clarity that both triggers are running the identical function.
Puppeteer Function
const puppeteer = require('puppeteer');
scrapeUglyWebsite = () => {
return new Promise(async(resolve, reject) => {
await puppeteer.launch({
headless: true,
args: ['--no-sandbox']
})
.then(async (browser) => {
const page = await browser.newPage();
await page.goto('http://suzannecollinsbooks.com/', {waitUntil: 'load', timeout: 0})
.then(async () => {
//Wait for content to load
await page.waitForFunction('document.body !== null && document.body.innerText.includes(\'Jon Scieszka\')');
//Evaluate page contents
const dom_eval = await page.evaluate(() => document.body.innerText.includes("Here’s a picture of me with a rat"));
await browser.close();
resolve(dom_eval);
});
}).catch((err) => {
reject(err);
});
});
};
HTTP Trigger - index.js
exports.cloudFunctionTest = (req, res) => {
scrapeUglyWebsite()
.then((results) => {
if(results) {
res.send('Suzanne Collins takes pictures with rats.');
} else {
res.send("Suzzane Collins doesn't take pictures with rats.");
};
})
.catch((err) => {
res.send(err.toString());
});
Pub/Sub Trgger - index.js
exports.cloudFunctionTest = (data, context) => {
scrapeUglyWebsite()
.then((results) => {
if(results) {
console.log('Suzanne Collins takes pictures with rats.');
} else {
console.log("Suzzane Collins doesn't take pictures with rats.");
};
})
.catch((err) => {
console.log(err.toString());
});
};
package.json
{
"name": "test",
"version": "0.0.1",
"engines": {
"node": "8"
},
"dependencies": {
"puppeteer": "^1.6.0"
}
}
HTTP Trigger behaves correctly with the expected result
Suzanne Collins takes pictures with rats.
Pub/Sub Trigger throws the following error with no output
TimeoutError: Timed out after 30000 ms while trying to connect to Chrome! The only Chrome revision guaranteed to work is r662092
I know this is late but the reason that the TimeoutError occurs is because cloud functions do not automatically wait for async tasks to finish completing. So in exports.cloudFunctionTest, scrapeUglyWebsite() is called but the function does not wait for the promise to be fulfilled, so the program terminates. Hence the error
More info here on how background functions work in NodeJs
In order for the function to wait for scrapeUglyWebsite(), you need to return a promise that completes when scrapeUglyWebsite() and the resulting code is complete.
Personally, I got it to work by simply wrapping the code currently in the function I am exporting in another async function and then returning the promise of the wrapper function.
async function wrapper() {
try {
const result = await scrapeUglyWebsite();
if(results) {
console.log('Suzanne Collins takes pictures with rats.');
} else {
console.log("Suzzane Collins doesn't take pictures with rats.");
};
} catch (err) {
console.log(err.toString());
}
}
Then in the function you want to export:
exports.cloudFunctionTest = (data, context) => {
return wrapper();
};
I am trying to capture the http response status from a user sign-up.
My code looks like this:
it.only('returns a 400 response if email is taken', async () => {
await page.goto(`${process.env.DOMAIN}/sign-up`)
await page.waitFor('input[id="Full Name"]')
await page.type('input[id="Full Name"]', 'Luke Skywalker')
await page.type('input[id="Email"]', 'LukeSkywalker#voyage.com')
await page.type('input[id="Password"]', 'LukeSkywalker123', {delay: 100})
await page.click('input[type="submit"]', {delay: 1000})
const response = await page.on('response', response => response)
console.log('request status', response.status)
// expect(response).toEqual(400)
})
The docs give an example of intercepting the request and doing things with it:
await page.setRequestInterception(true);
page.on('request', request => {
request.respond({
status: 404,
contentType: 'text/plain',
body: 'Not Found!'
});
});
And I have tried a similar pattern to no avail, along with many other patterns. Everything I do returns the page, a huge object with no status on it that I can see. Any help is much appreciated.
WHAT WORKED:
thank you to #tomahaug for steering me in the correct direction. My first problem was placement, the listener needs to go be set up before the request is made, I had it just after the request. Makes sense. My biggest issue was assigning the listener to a variable, so that I could call the expect as my last line. Assigning it to a variable caused the page to be returned. What I needed to do was just run the test inside the listener. While using done() throws and error for me I closed off my test as follows below, the working version of my code:
it.only('returns a 400 response if email is taken', async () => {
await page.goto(`${process.env.DOMAIN}/sign-up`)
await page.waitFor('input[id="Full Name"]')
await page.type('input[id="Full Name"]', 'Luke Skywalker')
await page.type('input[id="Email"]', 'LukeSkywalker#voyage1.com')
await page.type('input[id="Password"]', 'LukeSkywalker123', {delay: 100})
await page.on('response', response => {
if (response.request().method === 'POST' && response.url === `${process.env.USERS_API_DOMAIN}/sessions`) {
expect(response.status).toEqual(400)
}
})
await page.click('input[type="submit"]', {delay: 1000})
})
after(async function () {
await browser.close()
})
Hope this helps someone else!
I believe you should do something along those lines. Note the callback function done.
What the code does, is that it attaches a listener for responses, then clicks the submit button. When a response is received it checks the status code, asserts it, and terminates the test by calling done.
You might want to have an if-statement that checks that it is the actual response from your form that you are checking in the callback, as the response handler might emit events for other concurrent requests.
it.only('returns a 400 response if email is taken', () => {
await page.goto(`${process.env.DOMAIN}/sign-up`)
await page.waitFor('input[id="Full Name"]')
await page.type('input[id="Full Name"]', 'Luke Skywalker')
await page.type('input[id="Email"]', 'LukeSkywalker#voyage.com')
await page.type('input[id="Password"]', 'LukeSkywalker123', {delay: 100})
page.on('response', (response) => {
if (
response.request().method === 'POST' &&
response.url === `${process.env.USERS_API_DOMAIN}/sessions`)
{
expect(response.status).toEqual(400)
}
})
await page.click('input[type="submit"]', {delay: 1000})
})
I have not tested the code, but it should give you the right idea.
Edit: Adjusted to reflect what worked out in the end.
If you need to manipulate the request/response, use page.setRequestInterception(true) and page.on/page.once (as documented).
However, if all you need is to assert something about the response, the simplest and most idiomatic way to do so is with page.waitForResponse:
const updateDashboardResponse = await page.waitForResponse(response =>
response.url().includes('updateDashboard')
);
expect(updateDashboardResponse.status()).toBe(200);
This allows test flow to remain linear and avoids ambiguity around closing a test before a page.on handler receives a response event.
The accepted answer (which was also edited into the question) is incorrect. It introduces a race condition due to a 1 second delay added to the click call. At best, this slows down the test suite unnecessarily, and at worst it generates false failures should the request take longer than a second to resolve (unlikely if it's mocked, but it doesn't change the fact that the code is unsafe).
Whenever there's a callback in a Jest test case, the correct way to ensure it's been executed and all assertions depending on it firing have been made without adding artificial delays is to call done() from the callback. If there is a throw in the callback that makes done unreachable, call done(error) in the error handler to report the test case failure to Jest.
To do this, you'll need to add done as the parameter to the callback passed to the it, test or only function so that it's available in the block. This allows Jest's test runner to treat the test as asynchronous and not to resolve it until done is called. Without done, the test suite ignores the callback's assertions. async/await doesn't help because it's a separate asynchronous chain than the callback.
You only need to specify done as a parameter or return a promise (async implicitly returns a promise), never both. However, you'd still likely want to use await for Puppeteer library calls rather than then. You can use an async IIFE that eventually fires the done() call when all assertions have fired to get the best of both worlds.
For example,
it.only('returns a 400 response if email is taken', done => {
(async () => {
page.on('response', response => {
if (response.request().method === 'POST' &&
response.url === `${process.env.USERS_API_DOMAIN}/sessions`) {
try { /* try-catch pattern shown for illustration */
expect(response.status).toEqual(400);
done();
}
catch (err) {
done(err);
}
}
});
await page.goto(`${process.env.DOMAIN}/sign-up`);
await page.waitFor('input[id="Full Name"]');
await page.type('input[id="Full Name"]', 'Luke Skywalker');
await page.type('input[id="Email"]', 'LukeSkywalker#voyage.com');
await page.type('input[id="Password"]', 'LukeSkywalker123', {delay: 100});
await page.click('input[type="submit"]');
})();
});
With this in mind, this answer shows a likely better approach using waitForResponse which lets you skip the callback and done entirely. The callback to waitForResponse is a string URL or function predicate that should return true for the target response that's being waited on:
it.only('returns a 400 response if email is taken', async () => {
await page.goto(`${process.env.DOMAIN}/sign-up`);
await page.waitFor('input[id="Full Name"]');
await page.type('input[id="Full Name"]', 'Luke Skywalker');
await page.type('input[id="Email"]', 'LukeSkywalker#voyage.com');
await page.type('input[id="Password"]', 'LukeSkywalker123', {delay: 100});
await page.click('input[type="submit"]');
const response = await page.waitForResponse(response =>
response.request().method === 'POST' &&
response.url === `${process.env.USERS_API_DOMAIN}/sessions`
);
expect(response.status).toEqual(400);
});
I should also mention waitFor is deprecated in favor of waitForSelector in the above snippets and that .url and .method are functions. I haven't verified the above code; it's there to relate to the original post and show the high-level patterns.
Minimal example
index.html
This is the web page we're testing.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
</head>
<body>
<button>Post</button>
<script>
document
.querySelector("button")
.addEventListener("click", e =>
fetch("https://jsonplaceholder.typicode.com/posts", {
method: "POST",
body: JSON.stringify({
title: "foo",
body: "bar",
userId: 1,
}),
headers: {
"Content-type": "application/json; charset=UTF-8",
},
})
.then(response => response.json())
.then(json => console.log(json))
)
;
</script>
</body>
</html>
index.test.js (async/await version):
describe("index page", () => {
it("should respond to POST", async () => {
const url = "https://jsonplaceholder.typicode.com/posts";
await page.goto("http://localhost:1234", {waitUntil: "load"});
await page.click("button");
const response = await page.waitForResponse(response =>
response.request().method() === "POST" &&
response.url() === url
);
const expectedBody = {
body: "bar",
id: 101,
title: "foo",
userId: 1,
};
expect(await response.json()).toEqual(expectedBody);
});
});
index.test.js (then version):
describe("index page", () => {
it("should respond to POST", () => {
const url = "https://jsonplaceholder.typicode.com/posts";
const expectedBody = {
body: "bar",
id: 101,
title: "foo",
userId: 1,
};
return page.goto("http://localhost:1234", {
waitUntil: "load"
})
.then(() => page.click("button"))
.then(() => page.waitForResponse(response =>
response.request().method() === "POST" &&
response.url() === url
))
.then(response => response.json())
.then(body => expect(body).toEqual(expectedBody))
;
});
});
index.test.js (done version):
describe("index page", () => {
it("should respond to POST", done => {
(async () => {
const url = "https://jsonplaceholder.typicode.com/posts";
const expectedBody = {
body: "bar",
id: 101,
title: "foo",
userId: 1,
};
await page.setRequestInterception(true);
page.on("response", async response => {
if (response.request().method() === "POST" &&
response.url() === url) {
try {
const body = await response.json();
expect(body).toEqual(expectedBody);
done();
}
catch (err) {
done(err);
}
}
});
await page.goto("http://localhost:1234", {
waitUntil: "load"
});
page.click("button");
})();
});
});
response.url is a function and you have to call it:
response.url()
The same is for response.request().method:
response.request().method()
I am trying to render some JSON about a person's location from an api in my react app.
I am using isomorphic-fetch to access the data from the API I can add the base test in and it correctly logs the data using below.
require('isomorphic-fetch');
require('es6-promise').polyfill();
var url = 'http://localhost:3000/api/data'
fetch(url)
.then(function(response) {
if (response.status >= 400) {
throw new Error("Bad response from server");
}
return response.json();
})
.then(function(data) {
console.log(data);
});
What i'm trying to work out is how I can take this response and render it in my component which currently looks like this (in this example code below data is coming from local json file so i need to merge them together).
I've attempted to set up componentDidMount but could get my head around the syntax so it kept breaking, I also checked out redux actions but that exploded my brain.
const personLoc = Object.keys(data.person.loc).map((content, idx) => {
const items = data.person.loc[content].map((item, i) => (
<p key={i}>{item.text}</p>
))
return <div key={idx}>{items}</div>
})
export default function PersonLocation() {
return (
<div className="bio__location">
{personLoc}
</div>
)
}
componentDidMount should setState:
componentDidMount() {
var that = this;
var url = 'http://localhost:3000/api/data'
fetch(url)
.then(function(response) {
if (response.status >= 400) {
throw new Error("Bad response from server");
}
return response.json();
})
.then(function(data) {
that.setState({ person: data.person });
});
}
The render component should map the state:
const personLoc = Object.keys(this.state.person.loc).map((content, idx) => {
const items = this.state.person.loc[content].map((item, i) => (
<p key={i}>{item.text}</p>
))
return <div key={idx}>{items}</div>
})