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import { BufReader, ReadLineResult } from "./buf_reader.ts";import { getFilename } from "./content_disposition.ts";import { equals, extension, writeAll } from "./deps.ts";import { readHeaders, toParamRegExp, unquote } from "./headers.ts";import { httpErrors } from "./httpError.ts";import { getRandomFilename, skipLWSPChar, stripEol } from "./util.ts";
const decoder = new TextDecoder();const encoder = new TextEncoder();
const BOUNDARY_PARAM_REGEX = toParamRegExp("boundary", "i");const DEFAULT_BUFFER_SIZE = 1_048_576; // 1mbconst DEFAULT_MAX_FILE_SIZE = 10_485_760; // 10mbconst DEFAULT_MAX_SIZE = 0; // all files written to discconst NAME_PARAM_REGEX = toParamRegExp("name", "i");
export interface FormDataBody { /** A record of form parts where the key was the `name` of the part and the * value was the value of the part. This record does not include any files * that were part of the form data. * * *Note*: Duplicate names are not included in this record, if there are * duplicates, the last value will be the value that is set here. If there * is a possibility of duplicate values, use the `.stream()` method to * iterate over the values. */ fields: Record<string, string>;
/** An array of any files that were part of the form data. */ files?: FormDataFile[];}
/** A representation of a file that has been read from a form data body. */export type FormDataFile = { /** When the file has not been written out to disc, the contents of the file * as a `Uint8Array`. */ content?: Uint8Array;
/** The content type og the form data file. */ contentType: string;
/** When the file has been written out to disc, the full path to the file. */ filename?: string;
/** The `name` that was assigned to the form data file. */ name: string;
/** The `filename` that was provided in the form data file. */ originalName: string;};
export interface FormDataReadOptions { /** The size of the buffer to read from the request body at a single time. * This defaults to 1mb. */ bufferSize?: number;
/** The maximum file size that can be handled. This defaults to 10MB when * not specified. This is to try to avoid DOS attacks where someone would * continue to try to send a "file" continuously until a host limit was * reached crashing the server or the host. */ maxFileSize?: number;
/** The maximum size of a file to hold in memory, and not write to disk. This * defaults to `0`, so that all multipart form files are written to disk. * When set to a positive integer, if the form data file is smaller, it will * be retained in memory and available in the `.content` property of the * `FormDataFile` object. If the file exceeds the `maxSize` it will be * written to disk and the `filename` file will contain the full path to the * output file. */ maxSize?: number;
/** When writing form data files to disk, the output path. This will default * to a temporary path generated by `Deno.makeTempDir()`. */ outPath?: string;
/** When a form data file is written to disk, it will be generated with a * random filename and have an extension based off the content type for the * file. `prefix` can be specified though to prepend to the file name. */ prefix?: string;}
interface PartsOptions { body: BufReader; final: Uint8Array; maxFileSize: number; maxSize: number; outPath?: string; part: Uint8Array; prefix?: string;}
function append(a: Uint8Array, b: Uint8Array): Uint8Array { const ab = new Uint8Array(a.length + b.length); ab.set(a, 0); ab.set(b, a.length); return ab;}
function isEqual(a: Uint8Array, b: Uint8Array): boolean { return equals(skipLWSPChar(a), b);}
async function readToStartOrEnd( body: BufReader, start: Uint8Array, end: Uint8Array,): Promise<boolean> { let lineResult: ReadLineResult | null; while ((lineResult = await body.readLine())) { if (isEqual(lineResult.bytes, start)) { return true; } if (isEqual(lineResult.bytes, end)) { return false; } } throw new httpErrors.BadRequest( "Unable to find multi-part boundary.", );}
/** Yield up individual parts by reading the body and parsing out the ford * data values. */async function* parts( { body, final, part, maxFileSize, maxSize, outPath, prefix }: PartsOptions,): AsyncIterableIterator<[string, string | FormDataFile]> { async function getFile(contentType: string): Promise<[string, Deno.File]> { const ext = extension(contentType); if (!ext) { throw new httpErrors.BadRequest(`Invalid media type for part: ${ext}`); } if (!outPath) { outPath = await Deno.makeTempDir(); } const filename = `${outPath}/${getRandomFilename(prefix, ext)}`; const file = await Deno.open(filename, { write: true, createNew: true }); return [filename, file]; }
while (true) { const headers = await readHeaders(body); const contentType = headers["content-type"]; const contentDisposition = headers["content-disposition"]; if (!contentDisposition) { throw new httpErrors.BadRequest( "Form data part missing content-disposition header", ); } if (!contentDisposition.match(/^form-data;/i)) { throw new httpErrors.BadRequest( `Unexpected content-disposition header: "${contentDisposition}"`, ); } const matches = NAME_PARAM_REGEX.exec(contentDisposition); if (!matches) { throw new httpErrors.BadRequest( `Unable to determine name of form body part`, ); } let [, name] = matches; name = unquote(name); if (contentType) { const originalName = getFilename(contentDisposition); let byteLength = 0; let file: Deno.File | undefined; let filename: string | undefined; let buf: Uint8Array | undefined; if (maxSize) { buf = new Uint8Array(); } else { const result = await getFile(contentType); filename = result[0]; file = result[1]; } while (true) { const readResult = await body.readLine(false); if (!readResult) { throw new httpErrors.BadRequest("Unexpected EOF reached"); } const { bytes } = readResult; const strippedBytes = stripEol(bytes); if (isEqual(strippedBytes, part) || isEqual(strippedBytes, final)) { if (file) { // remove extra 2 bytes ([CR, LF]) from result file const bytesDiff = bytes.length - strippedBytes.length; if (bytesDiff) { const originalBytesSize = await file.seek( -bytesDiff, Deno.SeekMode.Current, ); await file.truncate(originalBytesSize); }
file.close(); } yield [ name, { content: buf, contentType, name, filename, originalName, } as FormDataFile, ]; if (isEqual(strippedBytes, final)) { return; } break; } byteLength += bytes.byteLength; if (byteLength > maxFileSize) { if (file) { file.close(); } throw new httpErrors.RequestEntityTooLarge( `File size exceeds limit of ${maxFileSize} bytes.`, ); } if (buf) { if (byteLength > maxSize) { const result = await getFile(contentType); filename = result[0]; file = result[1]; await writeAll(file, buf); buf = undefined; } else { buf = append(buf, bytes); } } if (file) { await writeAll(file, bytes); } } } else { const lines: string[] = []; while (true) { const readResult = await body.readLine(); if (!readResult) { throw new httpErrors.BadRequest("Unexpected EOF reached"); } const { bytes } = readResult; if (isEqual(bytes, part) || isEqual(bytes, final)) { yield [name, lines.join("\n")]; if (isEqual(bytes, final)) { return; } break; } lines.push(decoder.decode(bytes)); } } }}
/** A class which provides an interface to access the fields of a * `multipart/form-data` body. */export class FormDataReader { #body: Deno.Reader; #boundaryFinal: Uint8Array; #boundaryPart: Uint8Array; #reading = false;
constructor(contentType: string, body: Deno.Reader) { const matches = contentType.match(BOUNDARY_PARAM_REGEX); if (!matches) { throw new httpErrors.BadRequest( `Content type "${contentType}" does not contain a valid boundary.`, ); } let [, boundary] = matches; boundary = unquote(boundary); this.#boundaryPart = encoder.encode(`--${boundary}`); this.#boundaryFinal = encoder.encode(`--${boundary}--`); this.#body = body; }
/** Reads the multipart body of the response and resolves with an object which * contains fields and files that were part of the response. * * *Note*: this method handles multiple files with the same `name` attribute * in the request, but by design it does not handle multiple fields that share * the same `name`. If you expect the request body to contain multiple form * data fields with the same name, it is better to use the `.stream()` method * which will iterate over each form data field individually. */ async read(options: FormDataReadOptions = {}): Promise<FormDataBody> { if (this.#reading) { throw new Error("Body is already being read."); } this.#reading = true; const { outPath, maxFileSize = DEFAULT_MAX_FILE_SIZE, maxSize = DEFAULT_MAX_SIZE, bufferSize = DEFAULT_BUFFER_SIZE, } = options; const body = new BufReader(this.#body, bufferSize); const result: FormDataBody = { fields: {} }; if ( !(await readToStartOrEnd(body, this.#boundaryPart, this.#boundaryFinal)) ) { return result; } try { for await ( const part of parts({ body, part: this.#boundaryPart, final: this.#boundaryFinal, maxFileSize, maxSize, outPath, }) ) { const [key, value] = part; if (typeof value === "string") { result.fields[key] = value; } else { if (!result.files) { result.files = []; } result.files.push(value); } } } catch (err) { if (err instanceof Deno.errors.PermissionDenied) { console.error(err.stack ? err.stack : `${err.name}: ${err.message}`); } else { throw err; } } return result; }
/** Returns an iterator which will asynchronously yield each part of the form * data. The yielded value is a tuple, where the first element is the name * of the part and the second element is a `string` or a `FormDataFile` * object. */ async *stream( options: FormDataReadOptions = {}, ): AsyncIterableIterator<[string, string | FormDataFile]> { if (this.#reading) { throw new Error("Body is already being read."); } this.#reading = true; const { outPath, maxFileSize = DEFAULT_MAX_FILE_SIZE, maxSize = DEFAULT_MAX_SIZE, bufferSize = 32000, } = options; const body = new BufReader(this.#body, bufferSize); if ( !(await readToStartOrEnd(body, this.#boundaryPart, this.#boundaryFinal)) ) { return; } try { for await ( const part of parts({ body, part: this.#boundaryPart, final: this.#boundaryFinal, maxFileSize, maxSize, outPath, }) ) { yield part; } } catch (err) { if (err instanceof Deno.errors.PermissionDenied) { console.error(err.stack ? err.stack : `${err.name}: ${err.message}`); } else { throw err; } } }
[Symbol.for("Deno.customInspect")](inspect: (value: unknown) => string) { return `${this.constructor.name} ${inspect({})}`; }}