Method #handle

http/unstable_formdata_decoder_stream.ts:98–252

(
    readable: ReadableStream<Uint8Array>,
    boundary: Uint8Array,
  )

  }

  async *#handle(
    readable: ReadableStream<Uint8Array>,
    boundary: Uint8Array,
  ): AsyncGenerator<FormDataEntry> {
    const decoder = new TextDecoder();
    const reader = readable.pipeThrough(
      new CappedDelimiterStream({
        delimiter: Uint8Array.from([13, 10]),
        limit: 1024 * 8 - 2,
      }),
    ).getReader();

    let buffer = (await reader.read()).value?.value;
    // Ignore Preamble
    while (buffer != undefined) {
      if (
        buffer.length >= boundary.length &&
        boundary.every((x, i) => x === buffer![i])
      ) break;
      buffer = (await reader.read()).value?.value;
    }

    let defaultContentType = "text/plain; charset=UTF-8";
    while (
      buffer != undefined && buffer[boundary.length] !== 45 &&
      buffer[boundary.length + 1] !== 45
    ) {
      buffer = (await reader.read()).value?.value;
      if (buffer == undefined) throw new SyntaxError("Unexpected EOF");
      if (!buffer.length) {
        throw new SyntaxError(
          "Missing Content-Disposition header within FormData segment",
        );
      }

      // Header
      let name: string | undefined;
      let filename: string | undefined;
      let contentType = defaultContentType;
      do {
        const header = decoder.decode(buffer);
        if (header.startsWith("Content-Disposition:")) {
          const x = header
            .slice(header.indexOf(":") + 1)
            .split(";")
            .map((x) => x.trim());
          if (x.findIndex((x) => x === "form-data") === -1) {
            throw new SyntaxError("Content-Disposition was not of form-data");
          }
          name = x
            .find((x) => x.startsWith("name="))
            ?.split("=")[1];
          if (name == undefined) {
            throw new SyntaxError("Content-Disposition missing name field");
          }
          if (name.startsWith('"')) name = name.slice(1, -1);

          filename = x