refactor: better proxy clipboard autofill

src/lib/proxy-string.test.mjs

@@ -0,0 +1,129 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import {
+  CREDENTIALS_FIRST_FORMAT,
+  HOST_FIRST_FORMAT,
+  pickParsedProxy,
+  resolveAmbiguousProxyLine,
+  splitProxyScheme,
+} from "./proxy-string.ts";
+
+/**
+ * The formats themselves are exercised in Rust
+ * (`proxy_manager::tests::test_proxy_txt_parsing_various_formats`). What is
+ * pinned here is the frontend's half: the scheme survives an ambiguous line,
+ * and a resolution that doesn't fit the line is refused rather than turned into
+ * a proxy pointing at somebody's password.
+ */
+
+test("a bare line is HTTP", () => {
+  assert.deepEqual(splitProxyScheme("1.2.3.4:8080"), {
+    proxyType: "http",
+    rest: "1.2.3.4:8080",
+  });
+});
+
+test("known schemes are recognised and normalised", () => {
+  assert.deepEqual(splitProxyScheme("SOCKS://1.2.3.4:1080"), {
+    proxyType: "socks5",
+    rest: "1.2.3.4:1080",
+  });
+  assert.equal(splitProxyScheme("shadowsocks://host:8388").proxyType, "ss");
+});
+
+test("an unknown scheme is left in the body rather than guessed at", () => {
+  assert.deepEqual(splitProxyScheme("ftp://1.2.3.4:21"), {
+    proxyType: "http",
+    rest: "ftp://1.2.3.4:21",
+  });
+});
+
+test("host-first resolution keeps the scheme", () => {
+  assert.deepEqual(
+    resolveAmbiguousProxyLine(
+      "socks5://1234:5678:9012:3456",
+      HOST_FIRST_FORMAT,
+    ),
+    {
+      proxy_type: "socks5",
+      host: "1234",
+      port: 5678,
+      username: "9012",
+      password: "3456",
+      original_line: "socks5://1234:5678:9012:3456",
+    },
+  );
+});
+
+test("credentials-first resolution reads the tail as the endpoint", () => {
+  assert.deepEqual(
+    resolveAmbiguousProxyLine("1234:5678:9012:3456", CREDENTIALS_FIRST_FORMAT),
+    {
+      proxy_type: "http",
+      host: "9012",
+      port: 3456,
+      username: "1234",
+      password: "5678",
+      original_line: "1234:5678:9012:3456",
+    },
+  );
+});
+
+test("a format that doesn't fit the line resolves to nothing", () => {
+  // 70000 is past the port range, so this ordering cannot be the right one.
+  assert.equal(
+    resolveAmbiguousProxyLine("host:70000:user:pass", HOST_FIRST_FORMAT),
+    null,
+  );
+  assert.equal(resolveAmbiguousProxyLine("host:8080", HOST_FIRST_FORMAT), null);
+  assert.equal(
+    resolveAmbiguousProxyLine("a:1:b:2", "host:port:user:password"),
+    null,
+  );
+});
+
+test("the first parsed line of a multi-line paste wins", () => {
+  const parsed = pickParsedProxy([
+    { status: "invalid", line: "notaproxy", reason: "nope" },
+    {
+      status: "parsed",
+      proxy_type: "socks5",
+      host: "1.2.3.4",
+      port: 1080,
+      username: "u",
+      password: "p",
+      original_line: "socks5://u:p@1.2.3.4:1080",
+    },
+    {
+      status: "parsed",
+      proxy_type: "http",
+      host: "5.6.7.8",
+      port: 80,
+      original_line: "5.6.7.8:80",
+    },
+  ]);
+  assert.equal(parsed?.host, "1.2.3.4");
+  assert.equal(parsed?.proxy_type, "socks5");
+});
+
+test("an ambiguous paste falls back to host:port:username:password", () => {
+  const parsed = pickParsedProxy([
+    {
+      status: "ambiguous",
+      line: "1234:5678:9012:3456",
+      possible_formats: [HOST_FIRST_FORMAT, CREDENTIALS_FIRST_FORMAT],
+    },
+  ]);
+  assert.equal(parsed?.host, "1234");
+  assert.equal(parsed?.port, 5678);
+});
+
+test("nothing usable yields null so the plain paste stands", () => {
+  assert.equal(
+    pickParsedProxy([
+      { status: "invalid", line: "proxy.example.com", reason: "" },
+    ]),
+    null,
+  );
+  assert.equal(pickParsedProxy([]), null);
+});

src/lib/proxy-string.ts

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+/**
+ * Reading a proxy out of a pasted line.
+ *
+ * The parser itself is Rust's `parse_txt_proxies`
+ * (`src-tauri/src/proxy_manager.rs`); both the import dialog and the add/edit
+ * form hand their clipboard text to it rather than re-implementing the format
+ * zoo. What is left for the frontend is the part the backend deliberately
+ * refuses to decide: `a:b:c:d` is either `host:port:username:password` or
+ * `username:password:host:port`, and when both middle fields parse as a port
+ * only the user knows which. The backend reports that as `ambiguous`; the
+ * functions below turn the user's answer back into a proxy.
+ *
+ * Kept free of runtime imports so `proxy-string.test.mjs` can load it directly.
+ */
+
+import type { ParsedProxyLine, ProxyParseResult } from "@/types";
+
+/** URL schemes the Rust parser accepts, mapped onto the stored proxy type. */
+const PROXY_SCHEMES: Record<string, string> = {
+  http: "http",
+  https: "https",
+  socks: "socks5",
+  socks4: "socks4",
+  socks5: "socks5",
+  ss: "ss",
+  shadowsocks: "ss",
+  vless: "vless",
+};
+
+/** What a line carrying no scheme is assumed to be. */
+export const DEFAULT_PROXY_TYPE = "http";
+
+export const HOST_FIRST_FORMAT = "host:port:username:password";
+export const CREDENTIALS_FIRST_FORMAT = "username:password:host:port";
+
+/**
+ * Separates `socks5://1.2.3.4:1080` into its scheme and body. An unknown or
+ * absent scheme leaves the body untouched and falls back to HTTP, which is what
+ * the backend does with a bare `host:port`.
+ */
+export function splitProxyScheme(line: string): {
+  proxyType: string;
+  rest: string;
+} {
+  const separator = line.indexOf("://");
+  if (separator === -1) {
+    return { proxyType: DEFAULT_PROXY_TYPE, rest: line };
+  }
+
+  const proxyType = PROXY_SCHEMES[line.slice(0, separator).toLowerCase()];
+  return proxyType
+    ? { proxyType, rest: line.slice(separator + 3) }
+    : { proxyType: DEFAULT_PROXY_TYPE, rest: line };
+}
+
+/**
+ * Builds a proxy from a four-part line once the user has said which of the two
+ * orderings it uses. Returns null when the chosen ordering doesn't actually fit
+ * the line, so a stale selection can't produce a proxy pointing at a password.
+ */
+export function resolveAmbiguousProxyLine(
+  line: string,
+  format: string,
+): ParsedProxyLine | null {
+  const trimmed = line.trim();
+  const { proxyType, rest } = splitProxyScheme(trimmed);
+  const parts = rest.split(":");
+  if (parts.length !== 4) {
+    return null;
+  }
+
+  const hostFirst = format === HOST_FIRST_FORMAT;
+  if (!hostFirst && format !== CREDENTIALS_FIRST_FORMAT) {
+    return null;
+  }
+
+  const host = hostFirst ? parts[0] : parts[2];
+  const port = Number.parseInt(hostFirst ? parts[1] : parts[3], 10);
+  if (!host || !Number.isInteger(port) || port < 1 || port > 65535) {
+    return null;
+  }
+
+  return {
+    proxy_type: proxyType,
+    host,
+    port,
+    username: hostFirst ? parts[2] : parts[0],
+    password: hostFirst ? parts[3] : parts[1],
+    original_line: trimmed,
+  };
+}
+
+/**
+ * Picks the proxy to use out of a parse of pasted text. Only the first usable
+ * line matters: the form holds one proxy, and a paste that happens to carry a
+ * whole list should still fill it in rather than do nothing.
+ *
+ * Ambiguous lines resolve as `host:port:username:password`, the ordering the
+ * import dialog offers first and the one vendors overwhelmingly ship.
+ */
+export function pickParsedProxy(
+  results: ProxyParseResult[],
+): ParsedProxyLine | null {
+  for (const result of results) {
+    if (result.status === "parsed") {
+      return {
+        proxy_type: result.proxy_type,
+        host: result.host,
+        port: result.port,
+        username: result.username,
+        password: result.password,
+        vless_uri: result.vless_uri,
+        original_line: result.original_line,
+      };
+    }
+    if (result.status === "ambiguous") {
+      const resolved = resolveAmbiguousProxyLine(
+        result.line,
+        HOST_FIRST_FORMAT,
+      );
+      if (resolved) {
+        return resolved;
+      }
+    }
+  }
+  return null;
+}