angular实现IM聊天图片发送实例

/**
 * 黏贴发送图片
 * @param e
 */
pasteData(e) {
  e.preventDefault();
  let clipboardData = e.clipboardData;
  if (clipboardData) { //如果支持这个
    let items = clipboardData.items; //获取黏贴里的对象
    if (!items) {
      return;
    }
    let item;
    let types = clipboardData.types || [];
    for (let i = 0, len = types.length; i< len; i++) {
      if (types[i] === 'Files') {
        item = items[i];
        break;
      }
    }
    if (item && item.kind === 'file' && item.type.match(/^image\//i)) {
      imgReader(item);
    }
  }
  functionimgReader(obj){
   let $messageBox=$('#message-boxID');
    let file = obj.getAsFile(),
      reader = new FileReader();
    // 读取文件
    reader.readAsDataURL(file);
    reader.onload = function(e){
      let img = new Image();
      img.src = e.target['result'];
      img.className = 'chatImg';

      $messageBox.append(img);
      setTimeout(()=> {
        $messageBox.scrollTop($messageBox[0].scrollHeight);
      }, 0)
    };
  }
}

<inputid="upImg"name="fileTrans"type="file"(change)="onFileSelect($event)"/>

/**
 * 选择图片
 * @param event
 */
files:any[]=[];
onFileSelect(event) {
  this.files=[];
  let files = event.dataTransfer ? event.dataTransfer.files : event.target.files;
  let file;
  for (let i = 0; i < files.length; i++) {
    file = files[i];
    if (this.isImage(file)) {
      file.objectURL = this.sanitizer.bypassSecurityTrustUrl((window.URL.createObjectURL(files[i])));
      this.files.push(files[i]);
    }
  }
  let fileUrl = file.objectURL.changingThisBreaksApplicationSecurity;
  let img = new Image();
  img.src = fileUrl;
  img.className = 'chatImg';

  $('#message-boxID').append(img);
}

url:string="http://localhost:8080/upload";
progress:number=0;//进度

uploadPic(formData):Promise<any> {
   let xhr = new XMLHttpRequest(),
   
   
   //封装xhr请求
   return new Pormise(resolve,reject){
     xhr.upload.addEventListener('progress', (e: ProgressEvent) => {
     if(e.lengthComputable) {
      this.progress = Math.round((e.loaded * 100) / e.total);
     }
     }, false);

     xhr.onreadystatechange = ()=> {
       if(xhr.readyState == 4) {
         this.progress = 0;
         
         if(xhr.status >= 200 && xhr.status < 300)
           resolve({xhr: xhr, files: this.files});
         else
           reject({xhr: xhr, files: this.files});
       }
     };
     
     xhr.open('POST', this.url, true);
     //jwt后端验证，设置请求头部信息，解决跨域
     xhr.setRequestHeader("Authorization", "Basic " + localStorage.getItem('jwt'));
     
     xhr.send(formData);
   }
 }

/**
 * dataURL to blob, ref to https://gist.github.com/fupslot/5015897
 * @param dataURI
 * @returns {Blob}
 */
functiondataURItoBlob(dataURI){
  var byteString = atob(dataURI.split(',')[1]);
  var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
  var ab = new ArrayBuffer(byteString.length);
  var ia = new Uint8Array(ab);
  for (var i = 0; i < byteString.length; i++) {
    ia[i] = byteString.charCodeAt(i);
  }
  return new Blob([ab], {type: mimeString});
}

/**
   * 发送消息
   * @param taskValue
   */
  sendMessage() {
    let dateTime = this.dateFromat.FormatDate(new Date());
    let value = $('#message-boxID').html();
    let isImg = value.includes('<img');
    //如果是图片信息
    if (isImg) {
      let formData = new FormData();
      let dataURL="";
      let src=$(value)[0].src;
      //图片截图粘贴
      if(src.includes('data:images')){
        dataURL=src;
        let blob = dataURItoBlob(dataURL);
        formData.append('file', blob);
      
      //图片本地选择
      }else if(src.includes('blob:http')){
         //files是图片选择时保存的图片文件对象，见onFileSelect方法
        for(let i = 0; i < this.files.length; i++) {
          formData.append('file', this.files[i], this.files[i].name);
        }
      }
      //调用上传图片方法
      this.uploadFileService.uploadPic(formData).then(result=>{
        //上传成功，do something
        console.log(result);
        
      }).catch(err=>{
        console.log('图片上传失败'+err);
      })
    }else{
      //非图片信息，文本发送
      //this.submitMessage(value);
    }

  }