PIN-Based Auth の request_token 取得を実装

src/twitter.ts

@@ -0,0 +1,3 @@
+import { fetchRequestToken } from "./twitter/oauth/request_token.ts";
+
+console.log(await fetchRequestToken());

src/twitter/oauth/oauth_headers.ts

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+import { config } from "https://deno.land/x/dotenv/mod.ts";
+import { v4 } from "https://deno.land/std@0.51.0/uuid/mod.ts";
+import { hmac } from "https://deno.land/x/hmac@v2.0.1/mod.ts";
+import { percentEncode, toQueryParams } from "../../util.ts";
+
+type MethodType = "GET" | "POST";
+
+interface Options {
+  [key: string]: string;
+}
+
+class OAuthHeader {
+  method: MethodType;
+  url: string;
+  options: Options;
+
+  conf = config();
+  oauthVersion = "1.0";
+  oauthSignatureMethod = "HMAC-SHA1";
+  oauthNonce = this.generateNonce();
+  oauthTimestamp = this.getCurrentTimestamp();
+
+  constructor(method: MethodType, url: string, options: Options = {}) {
+    this.method = method;
+    this.url = url;
+    this.options = options;
+  }
+
+  create() {
+    const oauthSignature = this.createSignature();
+    const authorizationHeader = [
+      "OAuth",
+      `oauth_consumer_key="${this.conf.consumerApiKey}",`,
+      `oauth_nonce="${this.oauthNonce}",`,
+      `oauth_signature="${oauthSignature}",`,
+      `oauth_signature_method="${this.oauthSignatureMethod}",`,
+      `oauth_timestamp="${this.oauthTimestamp}",`,
+      `oauth_version="${this.oauthVersion}"`,
+    ].join(" ");
+
+    return new Headers({
+      "Authorization": authorizationHeader,
+      "Content-Type": "application/json",
+    });
+  }
+
+  private generateNonce(): string {
+    return v4.generate().replace(/-/g, "");
+  }
+
+  private getCurrentTimestamp(): string {
+    return Math.floor(Date.now() / 1000).toString();
+  }
+
+  // https://developer.twitter.com/en/docs/authentication/oauth-1-0a/creating-a-signature
+  private createSignature() {
+    // oauth_token is unnecessary for PIN-Based OAuth
+    const allParams: Options = {
+      ...this.options,
+      "oauth_consumer_key": this.conf.consumerApiKey,
+      "oauth_nonce": this.oauthNonce,
+      "oauth_signature_method": this.oauthSignatureMethod,
+      "oauth_timestamp": this.oauthTimestamp,
+      "oauth_version": this.oauthVersion,
+    };
+
+    const encodedParamPairs = toQueryParams(allParams, true);
+
+    const signatureBaseString = `${this.method}&${percentEncode(this.url)}&${
+      percentEncode(encodedParamPairs)
+    }`;
+
+    const signingKey = `${percentEncode(this.conf.consumerApiSecret)}&`;
+
+    const signature = hmac(
+      "sha1",
+      signingKey,
+      signatureBaseString,
+      "utf8",
+      "base64",
+    ).toString();
+
+    return percentEncode(signature);
+  }
+}
+
+export const createOAuthHeaders = (
+  method: MethodType,
+  url: string,
+  options: Options,
+) => {
+  const headers = new OAuthHeader(method, url, options);
+  return headers.create();
+};

src/twitter/oauth/request_token.ts

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+import { createOAuthHeaders } from "./oauth_headers.ts";
+import { toQueryParams } from "../../util.ts";
+
+const requestTokenUrl = "https://api.twitter.com/oauth/request_token";
+
+export const fetchRequestToken = async (): Promise<string> => {
+  const method = "POST";
+  const options = { "oauth_callback": "oob" };
+  const headers = createOAuthHeaders(method, requestTokenUrl, options);
+
+  const response = await fetch(requestTokenUrl + "?" + toQueryParams(options), {
+    method,
+    headers,
+  });
+  return await response.text();
+};

src/util.ts

@@ -0,0 +1,49 @@
+export const percentEncode = (val: string): string => {
+  const encodedVal: string = encodeURIComponent(val);
+
+  // Adjust for RFC 3986 section 2.2 Reserved Characters
+  const reservedChars: { match: RegExp; replace: string }[] = [
+    { match: /\!/g, replace: "%21" },
+    { match: /\#/g, replace: "%23" },
+    { match: /\$/g, replace: "%24" },
+    { match: /\&/g, replace: "%26" },
+    { match: /\'/g, replace: "%27" },
+    { match: /\(/g, replace: "%28" },
+    { match: /\)/g, replace: "%29" },
+    { match: /\*/g, replace: "%2A" },
+    { match: /\+/g, replace: "%2B" },
+    { match: /\,/g, replace: "%2C" },
+    { match: /\//g, replace: "%2F" },
+    { match: /\:/g, replace: "%3A" },
+    { match: /\;/g, replace: "%3B" },
+    { match: /\=/g, replace: "%3D" },
+    { match: /\?/g, replace: "%3F" },
+    { match: /\@/g, replace: "%40" },
+    { match: /\[/g, replace: "%5B" },
+    { match: /\]/g, replace: "%5D" },
+  ];
+
+  const percentEncodedVal = reservedChars.reduce(
+    (tot, { match, replace }) => {
+      return tot.replace(match, replace);
+    },
+    encodedVal,
+  );
+
+  return percentEncodedVal;
+};
+
+type Object = { [key: string]: string };
+
+export const toQueryParams = (
+  object: Object,
+  sort = false,
+): string => {
+  const strings = Object.entries(object).map(([key, val]) => {
+    const encodedKey = percentEncode(key);
+    const encodedVal = percentEncode(val);
+    return `${encodedKey}=${encodedVal}`;
+  });
+  if (sort) strings.sort();
+  return strings.join("&");
+};