整體

服務(wù)端從basicServer.js開始, 在此以之前的Basic Example的客戶端發(fā)送的CreteToken為例子, 服務(wù)端的http框架監(jiān)聽到該請求后開始處理, 對發(fā)送過來的消息進(jìn)行解析之后霞赫，調(diào)用getOrCreateRoom創(chuàng)建room和token.

//licode\extras\basic_example\basicServer.js

app.post('/createToken/', (req, res) => {
  console.log('Creating token. Request body: ', req.body);

  const username = req.body.username;
  const role = req.body.role;

  let room = defaultRoomName;
  let type;
  let roomId;
  let mediaConfiguration;

  if (req.body.room) room = req.body.room;
  if (req.body.type) type = req.body.type;
  if (req.body.roomId) roomId = req.body.roomId;
  if (req.body.mediaConfiguration) mediaConfiguration = req.body.mediaConfiguration;

  const createToken = (tokenRoomId) => {
    N.API.createToken(tokenRoomId, username, role, (token) => {
      console.log('Token created', token);
      res.send(token);
    }, (error) => {
      console.log('Error creating token', error);
      res.status(401).send('No Erizo Controller found');
    });
  };

  if (roomId) {
    createToken(roomId);
  } else {
    getOrCreateRoom(room, type, mediaConfiguration, createToken); //調(diào)用到此處創(chuàng)建房間湃鹊，創(chuàng)建token
  }
});

getOrCreateRoom中使用了N.API.getRooms()去向nuve獲取房間列表测柠，校驗當(dāng)前的房間是否已經(jīng)創(chuàng)建水醋，如果創(chuàng)建了則使用該room去創(chuàng)建token, 如果沒有則使用N.API.createRoom()創(chuàng)建房間之后再去創(chuàng)建token.

const getOrCreateRoom = (name, type = 'erizo', mediaConfiguration = 'default',
  callback = () => {}) => {
  if (name === defaultRoomName && defaultRoom) {
    callback(defaultRoom);
    return;
  }

//向NUVE發(fā)請求獲取房間列表蹬竖，如果該room存在林艘，使用這個room創(chuàng)建token,
//不存在灰伟，創(chuàng)建room之后再創(chuàng)建token
  N.API.getRooms((roomlist) => {
    let theRoom = '';
    const rooms = JSON.parse(roomlist);
    for (let i = 0; i < rooms.length; i += 1) {
      const room = rooms[i];
      if (room.name === name &&
                room.data &&
                room.data.basicExampleRoom) {
        theRoom = room._id;
        callback(theRoom);//create token
        return;
      }
    }
    const extra = { data: { basicExampleRoom: true }, mediaConfiguration };
    if (type === 'p2p') extra.p2p = true;

    N.API.createRoom(name, (roomID) => {
      theRoom = roomID._id;
      callback(theRoom);//create token
    }, () => {}, extra);
  });
};

此處的N.API是一個用來發(fā)送請求到后端nuve的工具類呆奕，提供了用戶的業(yè)務(wù)后臺到nuve的通訊接口峰尝，licode中的設(shè)計中偏窝，對于一些基礎(chǔ)的操作，createroken, createroom武学，deleteroom都通過nuve進(jìn)行處理祭往， 開發(fā)者的業(yè)務(wù)后臺只需要調(diào)用并同步信息即可，如以下兩個函數(shù), 主要是用send發(fā)送請求到nuve端

N.API = (function (N) {
    getRooms = function (callback, callbackError, params) {
        send(callback, callbackError, 'GET', undefined, 'rooms', params);
    };


    createRoom = function (name, callback, callbackError, options, params) {
        if (!options) {
            options = {};
        }

        send(function (roomRtn) {
            var room = JSON.parse(roomRtn);
            callback(room);
        }, callbackError, 'POST', {name: name, options: options}, 'rooms', params);
    };
}

nuve的起點在文件nuve.js中火窒，其上面也是用express作為監(jiān)聽的http框架硼补，去處理發(fā)送過來的請求，以createroom為例熏矿，如下所示已骇，一旦有請求，首先觸發(fā)對應(yīng)請求的鑒權(quán)票编，該鑒權(quán)就不細(xì)看了褪储，其會通過請求頭的service_id獲取一個service對象， 通過service進(jìn)行簽名校驗之后鑒權(quán)結(jié)束慧域，這個service相當(dāng)于在nuve的一個session, 可通過post鲤竹，get向nuve請求創(chuàng)建后返回id，后續(xù)請求需要帶上該id（注：但該Basic Example中的是預(yù)創(chuàng)建的）

// licode\nuve\nuveAPI\nuve.js

//鑒權(quán)
app.post('*', nuveAuthenticator.authenticate);

- createroom

鑒權(quán)通過后觸發(fā)roomsResource.createRoom進(jìn)行處理

// licode\nuve\nuveAPI\nuve.js

//監(jiān)聽創(chuàng)建房間的請求
app.post('/rooms', roomsResource.createRoom);

roomsResource.createRoom中使用roomRegistry.addRoom()往monogo中寫房間昔榴，寫庫成功后將roomid加入service.rooms數(shù)組中進(jìn)行管理

exports.createRoom = (req, res) => {
  let room;

  const currentService = req.service;
  //...省略...

  req.body.options = req.body.options || {};

  if (req.body.options.test) {
  //...省略...
  }
  else {
    room = { name: req.body.name };
    if (req.body.options.p2p) {
      room.p2p = true;
    }
    if (req.body.options.data) {
      room.data = req.body.options.data;
    }
    if (typeof req.body.options.mediaConfiguration === 'string') {
      room.mediaConfiguration = req.body.options.mediaConfiguration;
    }
    
    //addroom之后進(jìn)行
    roomRegistry.addRoom(room, (result) => {
      currentService.rooms.push(result); //將房間id(save返回的主鍵)放入數(shù)組
      serviceRegistry.addRoomToService(currentService, result);//將房間與service關(guān)聯(lián)起來
      log.info(`message: createRoom success, roomName:${req.body.name}, ` +
        `serviceId: ${currentService.name}, p2p: ${room.p2p}`);
      res.send(result);
    });
  }
};

- createtoken

創(chuàng)建完房間之后,basicServer發(fā)送請求創(chuàng)建token的請求辛藻，nuve監(jiān)聽到之后執(zhí)行,先通過doInit找到房間乘寒，然后去創(chuàng)建token

exports.create = (req, res) => {
//獲取room后執(zhí)行創(chuàng)建token的回調(diào)
  doInit(req, (currentService, currentRoom) => {
    if (currentService === undefined) {
      log.warn('message: createToken - service not found');
      res.status(404).send('Service not found');
      return;
    } else if (currentRoom === undefined) {
      log.warn(`message: createToken - room not found, roomId: ${req.params.room}`);
      res.status(404).send('Room does not exist');
      return;
    }
//創(chuàng)建token
    generateToken(req, (tokenS) => {
      if (tokenS === undefined) {
        res.status(401).send('Name and role?');
        return;
      }
      if (tokenS === 'error') {
        log.error('message: createToken error, errorMgs: No Erizo Controller available');
        res.status(404).send('No Erizo Controller found');
        return;
      }
      log.info(`message: createToken success, roomId: ${currentRoom._id}, ` +
        `serviceId: ${currentService._id}`);
      res.send(tokenS);
    });
  });
};

在generateToken()中，會將roomid辩撑，username等寫入到token中方面，還會分配ErizoController, 將erizoController的IP和port寫入到token中

const generateToken = (req, callback) => {
//....省略..... 

  token = {};
  token.userName = user;
  token.room = currentRoom._id;
  token.role = role;
  token.service = currentService._id;
  token.creationDate = new Date();
  token.mediaConfiguration = 'default';

//....省略..... 

//分配ErizoController, 將erizoController的IP和port寫入到token中
      cloudHandler.getErizoControllerForRoom(currentRoom, (ec) => {
      if (ec === 'timeout' || !ec) {
        callback('error');
        return;
      }

      token.secure = ec.ssl;
      if (ec.hostname !== '') {
        token.host = ec.hostname;
      } else {
        token.host = ec.ip;
      }

      token.host += `:${ec.port}`;

      tokenRegistry.addToken(token, (id, err) => {
        if (err) {
          return callback('error');
        }
        const tokenAdded = getTokenString(id, token);
        return callback(tokenAdded);
      });

};

獲取tErizoController的過程如下，首先通過room->erizoControllerId去獲取erizoController, 如果沒有的話岩榆，通過策略從隊列中獲取erizoController错负， 如果沒有策略，則遍歷隊列勇边，根據(jù)狀態(tài)返回一個可用的erizoController隊列犹撒，獲取其首元素進(jìn)行使用。

const getErizoControllerForRoom = (room, callback) => {
  const roomId = room._id;

//通過room->erizoControllerId去獲取erizoController
  roomRegistry.getRoom(roomId, (roomResult) => {
    const id = roomResult.erizoControllerId;
    if (id) {
      erizoControllerRegistry.getErizoController(id, (erizoController) => {
        if (erizoController) {
          callback(erizoController);
        } else {
          roomResult.erizoControllerId = undefined;
          roomRegistry.updateRoom(roomResult._id, roomResult);
          getErizoControllerForRoom(roomResult, callback);
        }
      });
      return;
    }

    let attempts = 0;
    let intervalId;

// 如果room->erizoControllerId是空的粒褒，從erizoController獲取
    getEcQueue((ecQueue) => {
      intervalId = setInterval(() => {
        let erizoController;
        if (getErizoController) {
//通過策略獲取
          erizoController = getErizoController(room, ecQueue);
        } else {
//從隊列獲取
          erizoController = ecQueue[0];
        }
        const erizoControllerId = erizoController ? erizoController._id : undefined;

        if (erizoControllerId !== undefined) {
          assignErizoController(erizoControllerId, room, (assignedEc) => {
            callback(assignedEc);
            clearInterval(intervalId);
          });
        }

        if (attempts > TOTAL_ATTEMPTS_EC_READY) {
          clearInterval(intervalId);
          callback('timeout');
        }
        attempts += 1;
      }, INTERVAL_TIME_EC_READY);
    });
  });
};