App.tsx•3.34 kB
import { FormEvent, useRef, useState } from "react";
import { useMutation, useQuery } from "convex/react";
import { api } from "../convex/_generated/api";
export default function App() {
const messages = useQuery(api.messages.list) || [];
const [newMessageText, setNewMessageText] = useState("");
const sendMessage = useMutation(api.messages.sendMessage);
const [name] = useState(() => "User " + Math.floor(Math.random() * 10000));
async function handleSendMessage(event: FormEvent) {
event.preventDefault();
if (newMessageText) {
await sendMessage({ body: newMessageText, author: name });
}
setNewMessageText("");
}
// @snippet start handlers
const generateUploadUrl = useMutation(api.messages.generateUploadUrl);
const sendImage = useMutation(api.messages.sendImage);
const imageInput = useRef<HTMLInputElement>(null);
const [selectedImage, setSelectedImage] = useState<File | null>(null);
async function handleSendImage(event: FormEvent) {
event.preventDefault();
// Step 1: Get a short-lived upload URL
const postUrl = await generateUploadUrl();
// Step 2: POST the file to the URL
const result = await fetch(postUrl, {
method: "POST",
headers: { "Content-Type": selectedImage!.type },
body: selectedImage,
});
const json = await result.json();
if (!result.ok) {
throw new Error(`Upload failed: ${JSON.stringify(json)}`);
}
const { storageId } = json;
// Step 3: Save the newly allocated storage id to the database
await sendImage({ storageId, author: name });
setSelectedImage(null);
imageInput.current!.value = "";
}
// @snippet end handlers
return (
<main>
<h1>Convex Chat</h1>
<p className="badge">
<span>{name}</span>
</p>
<ul>
{messages.map((message) => (
<li key={message._id}>
<span>{message.author}:</span>
{/* @snippet start useImageComponent */}
{message.format === "image" ? (
<Image message={message} />
) : (
<span>{message.body}</span>
)}
{/* @snippet end useImageComponent */}
<span>{new Date(message._creationTime).toLocaleTimeString()}</span>
</li>
))}
</ul>
<form onSubmit={handleSendMessage}>
<input
value={newMessageText}
onChange={(event) => setNewMessageText(event.target.value)}
placeholder="Write a message…"
/>
<input type="submit" value="Send" disabled={!newMessageText} />
</form>
{/* @snippet start formInput */}
<form onSubmit={handleSendImage}>
<input
type="file"
accept="image/*"
ref={imageInput}
onChange={(event) => setSelectedImage(event.target.files![0])}
className="ms-2 btn btn-primary"
disabled={selectedImage !== null}
/>
<input
type="submit"
value="Send Image"
disabled={selectedImage === null}
/>
</form>
{/* @snippet end formInput */}
</main>
);
}
// @snippet start imageComponent
function Image({ message }: { message: { url: string } }) {
return <img src={message.url} height="300px" width="auto" />;
}
// @snippet end imageComponent