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denoland-deno/textproto/mod.ts

154 lines
4.3 KiB
TypeScript

// Based on https://github.com/golang/go/blob/891682/src/net/textproto/
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
import { BufReader, BufState } from "../io/bufio.ts";
import { charCode } from "../io/util.ts";
const asciiDecoder = new TextDecoder();
function str(buf: Uint8Array): string {
if (buf == null) {
return "";
} else {
return asciiDecoder.decode(buf);
}
}
export class ProtocolError extends Error {
constructor(msg: string) {
super(msg);
this.name = "ProtocolError";
}
}
export function append(a: Uint8Array, b: Uint8Array): Uint8Array {
if (a == null) {
return b;
} else {
const output = new Uint8Array(a.length + b.length);
output.set(a, 0);
output.set(b, a.length);
return output;
}
}
export class TextProtoReader {
constructor(readonly r: BufReader) {}
/** readLine() reads a single line from the TextProtoReader,
* eliding the final \n or \r\n from the returned string.
*/
async readLine(): Promise<[string, BufState]> {
let [line, err] = await this.readLineSlice();
return [str(line), err];
}
/** ReadMIMEHeader reads a MIME-style header from r.
* The header is a sequence of possibly continued Key: Value lines
* ending in a blank line.
* The returned map m maps CanonicalMIMEHeaderKey(key) to a
* sequence of values in the same order encountered in the input.
*
* For example, consider this input:
*
* My-Key: Value 1
* Long-Key: Even
* Longer Value
* My-Key: Value 2
*
* Given that input, ReadMIMEHeader returns the map:
*
* map[string][]string{
* "My-Key": {"Value 1", "Value 2"},
* "Long-Key": {"Even Longer Value"},
* }
*/
async readMIMEHeader(): Promise<[Headers, BufState]> {
let m = new Headers();
let line: Uint8Array;
// The first line cannot start with a leading space.
let [buf, err] = await this.r.peek(1);
if (buf[0] == charCode(" ") || buf[0] == charCode("\t")) {
[line, err] = await this.readLineSlice();
}
[buf, err] = await this.r.peek(1);
if (err == null && (buf[0] == charCode(" ") || buf[0] == charCode("\t"))) {
throw new ProtocolError(
`malformed MIME header initial line: ${str(line)}`
);
}
while (true) {
let [kv, err] = await this.readLineSlice(); // readContinuedLineSlice
if (kv.byteLength == 0) {
return [m, err];
}
// Key ends at first colon; should not have trailing spaces
// but they appear in the wild, violating specs, so we remove
// them if present.
let i = kv.indexOf(charCode(":"));
if (i < 0) {
throw new ProtocolError(`malformed MIME header line: ${str(kv)}`);
}
let endKey = i;
while (endKey > 0 && kv[endKey - 1] == charCode(" ")) {
endKey--;
}
//let key = canonicalMIMEHeaderKey(kv.subarray(0, endKey));
let key = str(kv.subarray(0, endKey));
// As per RFC 7230 field-name is a token, tokens consist of one or more chars.
// We could return a ProtocolError here, but better to be liberal in what we
// accept, so if we get an empty key, skip it.
if (key == "") {
continue;
}
// Skip initial spaces in value.
i++; // skip colon
while (
i < kv.byteLength &&
(kv[i] == charCode(" ") || kv[i] == charCode("\t"))
) {
i++;
}
let value = str(kv.subarray(i));
// In case of invalid header we swallow the error
// example: "Audio Mode" => invalid due to space in the key
try {
m.append(key, value);
} catch {}
if (err != null) {
throw err;
}
}
}
async readLineSlice(): Promise<[Uint8Array, BufState]> {
// this.closeDot();
let line: Uint8Array;
while (true) {
let [l, more, err] = await this.r.readLine();
if (err != null) {
// Go's len(typed nil) works fine, but not in JS
return [new Uint8Array(0), err];
}
// Avoid the copy if the first call produced a full line.
if (line == null && !more) {
return [l, null];
}
line = append(line, l);
if (!more) {
break;
}
}
return [line, null];
}
}