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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import { DenoBlob } from "../blob.ts";
import { TextEncoder, TextDecoder } from "../text_encoding.ts";
import { getHeaderValueParams } from "../util.ts";
const decoder = new TextDecoder();
const encoder = new TextEncoder();
const CR = "\r".charCodeAt(0);
const LF = "\n".charCodeAt(0);
interface MultipartHeaders {
headers: Headers;
disposition: Map<string, string>;
}
export class MultipartParser {
readonly boundary: string;
readonly boundaryChars: Uint8Array;
readonly body: Uint8Array;
constructor(body: Uint8Array, boundary: string) {
if (!boundary) {
throw new TypeError("multipart/form-data must provide a boundary");
}
this.boundary = `--${boundary}`;
this.body = body;
this.boundaryChars = encoder.encode(this.boundary);
}
#parseHeaders = (headersText: string): MultipartHeaders => {
const headers = new Headers();
const rawHeaders = headersText.split("\r\n");
for (const rawHeader of rawHeaders) {
const sepIndex = rawHeader.indexOf(":");
if (sepIndex < 0) {
continue; // Skip this header
}
const key = rawHeader.slice(0, sepIndex);
const value = rawHeader.slice(sepIndex + 1);
headers.set(key, value);
}
return {
headers,
disposition: getHeaderValueParams(
headers.get("Content-Disposition") ?? ""
),
};
};
parse(): FormData {
const formData = new FormData();
let headerText = "";
let boundaryIndex = 0;
let state = 0;
let fileStart = 0;
for (let i = 0; i < this.body.length; i++) {
const byte = this.body[i];
const prevByte = this.body[i - 1];
const isNewLine = byte === LF && prevByte === CR;
if (state === 1 || state === 2 || state == 3) {
headerText += String.fromCharCode(byte);
}
if (state === 0 && isNewLine) {
state = 1;
} else if (state === 1 && isNewLine) {
state = 2;
const headersDone = this.body[i + 1] === CR && this.body[i + 2] === LF;
if (headersDone) {
state = 3;
}
} else if (state === 2 && isNewLine) {
state = 3;
} else if (state === 3 && isNewLine) {
state = 4;
fileStart = i + 1;
} else if (state === 4) {
if (this.boundaryChars[boundaryIndex] !== byte) {
boundaryIndex = 0;
} else {
boundaryIndex++;
}
if (boundaryIndex >= this.boundary.length) {
const { headers, disposition } = this.#parseHeaders(headerText);
const content = this.body.subarray(fileStart, i - boundaryIndex - 1);
// https://fetch.spec.whatwg.org/#ref-for-dom-body-formdata
const filename = disposition.get("filename");
const name = disposition.get("name");
state = 5;
// Reset
boundaryIndex = 0;
headerText = "";
if (!name) {
continue; // Skip, unknown name
}
if (filename) {
const blob = new DenoBlob([content], {
type: headers.get("Content-Type") || "application/octet-stream",
});
formData.append(name, blob, filename);
} else {
formData.append(name, decoder.decode(content));
}
}
} else if (state === 5 && isNewLine) {
state = 1;
}
}
return formData;
}
}
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