自動為 PTT 網頁版的文章代碼加上連結的 userscript

PTTWebAutoAIDLink.user.js

// ==UserScript==
// @name        PTT Web Auto AID Link
// @description 自動為 PTT 網頁版的文章代碼加上連結
// @namespace   https://www.ptt.cc/bbs
// @author      Shao-Chung Chen
// @license     MIT (http://opensource.org/licenses/MIT)
// @version     1.3.0
// @include     http://www.ptt.cc/*
// @include     https://www.ptt.cc/*
//
// @history     1.3 support post share syntax such as "※ [本文轉錄自 share 看板 #1Kx_iESk ]"
// @history     1.2 support board name syntax such as "#1ItZvO1L (C_and_CPP)"
// @history     1.1 recursively traverse all textNodes to prevent breaking <a> tags
// @history     1.0 initial commmit
// ==/UserScript==

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat
if (!String.prototype.repeat) {
  String.prototype.repeat = function(count) {
    'use strict';
    if (this == null) {
      throw new TypeError('can\'t convert ' + this + ' to object');
    }
    var str = '' + this;
    count = +count;
    if (count != count) {
      count = 0;
    }
    if (count < 0) {
      throw new RangeError('repeat count must be non-negative');
    }
    if (count == Infinity) {
      throw new RangeError('repeat count must be less than infinity');
    }
    count = Math.floor(count);
    if (str.length == 0 || count == 0) {
      return '';
    }
    // Ensuring count is a 31-bit integer allows us to heavily optimize the
    // main part. But anyway, most current (august 2014) browsers can't handle
    // strings 1 << 28 chars or longer, so:
    if (str.length * count >= 1 << 28) {
      throw new RangeError('repeat count must not overflow maximum string size');
    }
    var rpt = '';
    for (;;) {
      if ((count & 1) == 1) {
        rpt += str;
      }
      count >>>= 1;
      if (count == 0) {
        break;
      }
      str += str;
    }
    return rpt;
  }
}

String.prototype.rjust = function (width, padding) {
  padding = (padding || " ").substr(0, 1);
  if (this.length < width) {
    return padding.repeat(width - this.length) + this;
  }
  else {
    return this;
  }
};


var pttArticleUrlFromAidc = (function() {
  // 1. https://github.com/ptt/pttbbs/blob/master/mbbsd/aids.c
  // 2. https://github.com/ptt/pttbbs/blob/master/docs/aids.txt
  // 3. JavaScript bitwise operations are restricted in lower 32 bits
  var aid_base64_table = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_";
  var aidc2aidu = function (aidc) {
    var aidu = 0;
    for (var i = 0; i < aidc.length; i++) {
      var ch = aidc.charAt(i);
      var v = aid_base64_table.indexOf(ch);
      aidu = aidu * Math.pow(2, 6); // aidu <<= 6
      aidu = aidu - (aidu & 0x3f) + ((aidu & 0x3f) | (v & 0x3f)) // aidu |= (v & 0x3f);
    }
    return aidu;
  };
  var aidu2fn = function (aidu) {
    var type = ((aidu / Math.pow(2, 44)) & 0xf); // type = ((aidu >> 44) & 0xf);
    var v1 = ((aidu / Math.pow(2, 12)) & 0xffffffff); // v1 = ((aidu >> 12) & 0xffffffff);
    var v2 = (aidu & 0xfff);
    var filename = (type == 0 ? "M" : "G") + "." + v1.toString(10) + ".A." + v2.toString(16).toUpperCase().rjust(3, "0");
    return filename;
  };

  var buildUrl = function(boardName, fileName) {
    var protocol = window.location.protocol;
    var hostname = window.location.hostname;
    var port = window.location.port;
    var url = protocol + "//" + hostname + port + "/bbs/" + boardName + "/" + fileName + ".html";
    return url;
  };

  var boardNameFromUrl = window.location.pathname.match(/\/bbs\/([^\/]+)/)[1];
  return function (aidc, boardName) {
    // aidc should match [0-9a-zA-Z_\-]{8}
    var aidu = aidc2aidu(aidc);
    var fileName = aidu2fn(aidu);
    var articleUrl = buildUrl(boardName||boardNameFromUrl, fileName);
    console.log("aidc =", aidc, "boardName =", boardName);
    return articleUrl;
  };
})();


var linkifyAllAidsInContainer = function(containerDomObj) {
  var buildLinkNode = function (aid, url) {
    var a = document.createElement("a");
    a.href = url;
    a.target = "_blank";
    a.text = aid;
    return a;
  }

  // example: "share 看板 #1Kx_iESk" => [..., "share", "#1Kx_iESk"]
  // test: https://www.ptt.cc/bbs/Little-Games/M.1425013836.A.CDF.html
  var aidc_regexp1 = /(\S+)\s看板\s(#[0-9a-zA-Z_\-]{8})/;

  // example #1: "#1Kx_iESk" => [..., "#1Kx_iESk"]
  // example #2: "#1Kx_iESk (share)" => [..., "#1Kx_iESk", "share"]
  // text: https://www.ptt.cc/bbs/C_Chat/M.1411662330.A.526.html
  var aidc_regexp2 = /(#[0-9a-zA-Z_\-]{8})(?:\s?\((\S+)\))?/;

  // 1. "share 看板 #1Kx_iESk"
  // 2. "#1Kx_iESk"
  // 3. "#1Kx_iESk (share)"
  var aidc_regexp_split = /((?:\S+\s看板\s)?#[0-9a-zA-Z_\-]{8}(?:\s?\(\S+\))?)/;

  var linkifyAllAidsInTextNode = function(parentNode, textNode) {
    // split text node to "text node + <a> node + text node + ..." and insert back
    var originalText = textNode.nodeValue;
    if (aidc_regexp2.test(originalText)) {
      var newNodeList = [document.createTextNode(originalText)];
      while (true) {
        var lastNode = newNodeList.pop();
        if (lastNode.nodeType != Node.TEXT_NODE) {
          newNodeList.push(lastNode);
          break;
        }
        var textSegments = lastNode.nodeValue.split(aidc_regexp_split);
        if (textSegments.length == 1) {
          newNodeList.push(lastNode);
          break;
        }
        textSegments.forEach(function(textSegment, index) {
          if (m=textSegment.match(aidc_regexp1)) {
            var aidc = m[2].substr(1); // remove starting #
            var boardName = m[1]; // must exists
            var url = pttArticleUrlFromAidc(aidc, boardName);
            var linkNode = buildLinkNode(textSegment, url);
            newNodeList.push(linkNode);
          }
          else if (m=textSegment.match(aidc_regexp2)) {
            var aidc = m[1].substr(1); // remove starting #
            var boardName = m[2]; // undefined if not specified
            var url = pttArticleUrlFromAidc(aidc, boardName);
            var linkNode = buildLinkNode(textSegment, url);
            newNodeList.push(linkNode);
          }
          else {
            newNodeList.push(document.createTextNode(textSegment));
          }
        });
      };
      var jobFunc = function() {
        newNodeList.forEach(function(newNode, index) {
          parentNode.insertBefore(newNode, textNode);
        });
        parentNode.removeChild(textNode);
      };
      return jobFunc;
    };
    return undefined;
  };

  // cannot manipulate NodeList[] during iteration
  // hence we use a job queue to perform all replacements at last
  var jobFuncQueue = [];
  var linkifyAllAidsInAllTextNodesRecursively = function (parentNode) {
    var childNodes = parentNode.childNodes;
    [].forEach.call(childNodes, function(node, index) {
      switch(node.nodeType) {
        case Node.ELEMENT_NODE:
          // don't touch <a>, otherwise we may break links containing /#[0-9a-zA-Z_\-]{8}/
          if (node.tagName.toLowerCase() != "a") {
            linkifyAllAidsInAllTextNodesRecursively(node, node.childNodes);
          }
          break;
        case Node.TEXT_NODE:
          var jobFunc = linkifyAllAidsInTextNode(parentNode, node);
          if (jobFunc) {
            jobFuncQueue.push(jobFunc);
          }
          break;
      };
    });
  };

  linkifyAllAidsInAllTextNodesRecursively(containerDomObj);
  jobFuncQueue.forEach(function(jobFunc, index) {
    jobFunc();
  });
};


var linkifyAllAidsInPage = function() {
  var mainContent = document.querySelector('#main-content');
  linkifyAllAidsInContainer(mainContent);
};

if (window.location.host.toLowerCase().indexOf("ptt.cc") >= 0) {
  window.addEventListener("load", linkifyAllAidsInPage, false);
}