使用 API 路由构建表单

一个 HTML 表单会导致浏览器刷新页面或跳转到新页面。为了将表单数据发送到 API 端点，就必须要使用 JavaScript 拦截提交的表单。

本节示例向你展示了如何发送表单数据到一个 API 端点，并处理这些数据。

前期准备

段落标题 前期准备

• 一个开启了 SSR （output: ‘server’）模式的项目
• 安装一个集成的 UI 框架

操作步骤

段落标题 操作步骤

1. 在 /api/feedback 上创建一个 POST API 端点，用于接收表单数据。然后使用 request.formData() 处理表单数据。但在你使用表单值之前，请确保对其进行必要的校验。

   在这个示例中会向客户端发送一个包含响应消息的 JSON 对象。

   src/pages/api/feedback.ts

   import type { APIRoute } from "astro";
   
   export const POST: APIRoute = async ({ request }) => {
     const data = await request.formData();
     const name = data.get("name");
     const email = data.get("email");
     const message = data.get("message");
     // Validate the data - you'll probably want to do more than this
     if (!name || !email || !message) {
       return new Response(
         JSON.stringify({
           message: "Missing required fields",
         }),
         { status: 400 }
       );
     }
     // Do something with the data, then return a success response
     return new Response(
       JSON.stringify({
         message: "Success!"
       }),
       { status: 200 }
     );
   };

2. 使用你的 UI 框架创建一个表单组件。每个输入字段都应该有一个描述该输入值的 name 属性。

   请确保表单中包含一个 <button> 或 <input type="submit"> 元素，用于提交表单。

   Preact

   src/components/FeedbackForm.tsx

   export default function Form() {
     return (
       <form>
         <label>
           Name
           <input type="text" id="name" name="name" required />
         </label>
         <label>
           Email
           <input type="email" id="email" name="email" required />
         </label>
         <label>
           Message
           <textarea id="message" name="message" required />
         </label>
         <button>Send</button>
       </form>
     );
   }

   React

   src/components/FeedbackForm.tsx

   export default function Form() {
     return (
       <form>
         <label>
           Name
           <input type="text" id="name" name="name" required />
         </label>
         <label>
           Email
           <input type="email" id="email" name="email" required />
         </label>
         <label>
           Message
           <textarea id="message" name="message" required />
         </label>
         <button>Send</button>
       </form>
     );
   }

   Solid

   src/components/FeedbackForm.tsx

   export default function Form() {
     return (
       <form>
         <label>
           Name
           <input type="text" id="name" name="name" required />
         </label>
         <label>
           Email
           <input type="email" id="email" name="email" required />
         </label>
         <label>
           Message
           <textarea id="message" name="message" required />
         </label>
         <button>Send</button>
       </form>
     );
   }

   Svelte

   src/components/FeedbackForm.svelte

   <form>
     <label>
       Name
       <input type="text" id="name" name="name" required />
     </label>
     <label>
       Email
       <input type="email" id="email" name="email" required />
     </label>
     <label>
       Message
       <textarea id="message" name="message" required />
     </label>
     <button>Send</button>
   </form>

   Vue

   src/components/FeedbackForm.vue

   <template>
     <form>
       <label>
         Name
         <input type="text" id="name" name="name" required />
       </label>
       <label>
         Email
         <input type="email" id="email" name="email" required />
       </label>
       <label>
         Message
         <textarea id="message" name="message" required />
       </label>
       <button>Send</button>
     </form>
   </template>

3. 创建一个函数以接受提交事件（submit event），然后将其作为 submit 事件处理器传递给你的表单。

   在函数中：

   • 调用事件的 preventDefault() 方法，以覆盖浏览器的默认提交过程。
   • 创建一个 FormData 对象，并使用 fetch 将其以 POST 请求发送到你的端点。
   Preact

   src/components/FeedbackForm.tsx

   import { useState } from "preact/hooks";
   
   export default function Form() {
     const [responseMessage, setResponseMessage] = useState("");
   
     async function submit(e: SubmitEvent) {
       e.preventDefault();
       const formData = new FormData(e.target as HTMLFormElement);
       const response = await fetch("/api/feedback", {
         method: "POST",
         body: formData,
       });
       const data = await response.json();
       if (data.message) {
         setResponseMessage(data.message);
       }
     }
   
     return (
       <form onSubmit={submit}>
         <label>
           Name
           <input type="text" id="name" name="name" required />
         </label>
         <label>
           Email
           <input type="email" id="email" name="email" required />
         </label>
         <label>
           Message
           <textarea id="message" name="message" required />
         </label>
         <button>Send</button>
         {responseMessage && <p>{responseMessage}</p>}
       </form>
     );
   }

   React

   src/components/FeedbackForm.tsx

   import { useState } from "react";
   import type { FormEvent } from "react";
   
   export default function Form() {
     const [responseMessage, setResponseMessage] = useState("");
   
     async function submit(e: FormEvent<HTMLFormElement>) {
       e.preventDefault();
       const formData = new FormData(e.target as HTMLFormElement);
       const response = await fetch("/api/feedback", {
         method: "POST",
         body: formData,
       });
       const data = await response.json();
       if (data.message) {
         setResponseMessage(data.message);
       }
     }
   
     return (
       <form onSubmit={submit}>
         <label htmlFor="name">
           Name
           <input type="text" id="name" name="name" autoComplete="name" required />
         </label>
         <label htmlFor="email">
           Email
           <input type="email" id="email" name="email" autoComplete="email" required />
         </label>
         <label htmlFor="message">
           Message
           <textarea id="message" name="message" autoComplete="off" required />
         </label>
         <button>Send</button>
         {responseMessage && <p>{responseMessage}</p>}
       </form>
     );
   }

   Solid

   src/components/FeedbackForm.tsx

   import { createSignal, createResource, Suspense } from "solid-js";
   
   async function postFormData(formData: FormData) {
     const response = await fetch("/api/feedback", {
       method: "POST",
       body: formData,
     });
     const data = await response.json();
     return data;
   }
   
   export default function Form() {
     const [formData, setFormData] = createSignal<FormData>();
     const [response] = createResource(formData, postFormData);
   
     function submit(e: SubmitEvent) {
       e.preventDefault();
       setFormData(new FormData(e.target as HTMLFormElement));
     }
   
     return (
       <form onSubmit={submit}>
         <label>
           Name
           <input type="text" id="name" name="name" required />
         </label>
         <label>
           Email
           <input type="email" id="email" name="email" required />
         </label>
         <label>
           Message
           <textarea id="message" name="message" required />
         </label>
         <button>Send</button>
         <Suspense>{response() && <p>{response().message}</p>}</Suspense>
       </form>
     );
   }

   Svelte

   src/components/FeedbackForm.svelte

   <script lang="ts">
     let responseMessage: string;
   
     async function submit(e: SubmitEvent) {
       e.preventDefault();
       const formData = new FormData(e.currentTarget as HTMLFormElement);
       const response = await fetch("/api/feedback", {
         method: "POST",
         body: formData,
       });
       const data = await response.json();
       responseMessage = data.message;
     }
   </script>
   
   <form on:submit={submit}>
     <label>
       Name
       <input type="text" id="name" name="name" required />
     </label>
     <label>
       Email
       <input type="email" id="email" name="email" required />
     </label>
     <label>
       Message
       <textarea id="message" name="message" required />
     </label>
     <button>Send</button>
     {#if responseMessage}
       <p>{responseMessage}</p>
     {/if}
   </form>

   Vue

   src/components/FeedbackForm.vue

   <script setup lang="ts">
   import { ref } from "vue";
   
   const responseMessage = ref<string>();
   
   async function submit(e: Event) {
     e.preventDefault();
     const formData = new FormData(e.currentTarget as HTMLFormElement);
     const response = await fetch("/api/feedback", {
       method: "POST",
       body: formData,
     });
     const data = await response.json();
     responseMessage.value = data.message;
   }
   </script>
   
   <template>
     <form @submit="submit">
       <label>
         Name
         <input type="text" id="name" name="name" required />
       </label>
       <label>
         Email
         <input type="email" id="email" name="email" required />
       </label>
       <label>
         Message
         <textarea id="message" name="message" required />
       </label>
       <button>Send</button>
       <p v-if="responseMessage">{{ responseMessage }}</p>
     </form>
   </template>

4. 在一个页面中导入并包含你的 <FeedbackForm /> 组件。请确认使用了 client:* 指令以确保表单逻辑能在你需要的时候被激活。

   Preact

   src/pages/index.astro

   ---
   import FeedbackForm from "../components/FeedbackForm"
   ---
   <FeedbackForm client:load />

   React

   src/pages/index.astro

   ---
   import FeedbackForm from "../components/FeedbackForm"
   ---
   <FeedbackForm client:load />

   Solid

   src/pages/index.astro

   ---
   import FeedbackForm from "../components/FeedbackForm"
   ---
   <FeedbackForm client:load />

   Svelte

   src/pages/index.astro

   ---
   import FeedbackForm from "../components/FeedbackForm.svelte"
   ---
   <FeedbackForm client:load />

   Vue

   src/pages/index.astro

   ---
   import FeedbackForm from "../components/FeedbackForm.vue"
   ---
   <FeedbackForm client:load />