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@std/media-types
Overview Jump to heading
Utility functions for media types (MIME types).
This API is inspired by the GoLang mime
package and jshttp/mime-types,
and is designed to integrate and improve the APIs from
x/media_types.
The vendor folder contains copy of the
jshttp/mime-db db.json file,
along with its license.
import { contentType, allExtensions, getCharset } from "@std/media-types";
import { assertEquals } from "@std/assert";
assertEquals(allExtensions("application/json"), ["json", "map"]);
assertEquals(contentType(".json"), "application/json; charset=UTF-8");
assertEquals(getCharset("text/plain"), "UTF-8");
Add to your project Jump to heading
deno add jsr:@std/media-types
See all symbols in @std/media-types on
什么是媒体类型？ Jump to heading
媒体类型，也称为 MIME 类型，是用于标识文件或数据格式与性质的标准化标识符。它们通常用于 HTTP 头中，用以指定发送或接收内容的类型。
为什么使用 @std/media-types？ Jump to heading
在处理文件上传、下载或提供网页内容时，您可能需要基于文件扩展名确定正确的 MIME 类型，或反之亦然。此包提供实用函数，方便地在扩展名和 MIME 类型之间相互映射，并获取字符集提示。
示例 Jump to heading
快速查找 Jump to heading
import { allExtensions, extension, typeByExtension } from "@std/media-types";
console.log(typeByExtension(".png")); // "image/png"
console.log(extension("text/html")); // "html"
console.log(allExtensions("application/json")); // ["json", "map"]
构建响应头 Jump to heading
import { contentType } from "@std/media-types";
// 在合适时生成带有字符集的完整头部值
const ct = contentType(".css"); // "text/css; charset=UTF-8"
return new Response("body", {
headers: {
"Content-Type": ct ?? "application/octet-stream",
},
});
解析并规范化 Content-Type 头部 Jump to heading
import { formatMediaType, parseMediaType } from "@std/media-types";
const header = "text/HTML; charset=UTF-8";
const [type, params] = parseMediaType(header)!; // ["text/html", { charset: "UTF-8" }]
// 重新序列化，得到规范化的类型和参数（小写键）
const normalized = formatMediaType(type, params);
// "text/html; charset=UTF-8"
从请求中提取 multipart/form-data 边界 Jump to heading
import { parseMediaType } from "@std/media-types";
function getBoundary(headers: Headers): string | undefined {
const value = headers.get("content-type");
if (!value) return undefined;
const parsed = parseMediaType(value);
return parsed?.[1]?.boundary;
}
从接收到的请求检测字符集 Jump to heading
import { getCharset } from "@std/media-types";
async function readText(req: Request): Promise<string> {
const charset = getCharset(req.headers.get("content-type") ?? "") ?? "UTF-8";
const bytes = new Uint8Array(await req.arrayBuffer());
const decoder = new TextDecoder(charset);
return decoder.decode(bytes);
}
小贴士 Jump to heading
- 构建 HTTP 响应时，优选使用
contentType(extOrType)。 - 使用
allExtensions(type)来支持多种可能的扩展名。 parseMediaType在无效输入时会抛出异常；解析用户输入时请使用 try/catch 包裹。- 当
contentType()对未知扩展名或类型返回undefined，请回退使用application/octet-stream。