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Performing a Resumable Upload

If you have any questions during development, post them on the Issues page of GitHub. For details about parameters and usage of each API, see the API Reference.

The principle of resumable upload is to divide the files to be uploaded into several parts and upload them separately. The upload results are recorded in the resumable upload result in real time. The upload success result is returned only when all parts are successfully uploaded. If not all parts are successfully uploaded, an error code is returned in the callback function to remind the user to call the API again for upload.

You can call ObsClient.uploadFile to perform a resumable upload. The following table describes the parameters involved in this API.

Parameter

Description

Bucket

Bucket name

Key

Object name

RequestDate

Request time

NOTE:

When the parameter type is String, the value must comply with the ISO8601 or RFC822 standards.

VerifyMd5

Indicates whether to enable the consistency check for each part. The default value is false.

NOTE:

If this function is enabled, the overall uploading performance will be negatively affected and the browser will consume more CPU and memory resources.

SourceFile

Source file to be uploaded (The browser must support FileReader.)

UploadCheckpoint

Resumable upload recording object, which can be obtained through ResumeCallback.

PartSize

Part size, in bytes.

The value range is 100 KB to 5 GB. The default value is 9 MB.

TaskNum

Maximum number of parts that can be concurrently uploaded. The default value is 1.

ProgressCallback

Callback function for obtaining the upload progress

NOTE:

This callback function contains the following parameters in sequence: Number of uploaded bytes, total bytes, and used time (unit: second).

EventCallback

Callback function for obtaining the upload event

NOTE:

The callback function contains the following parameters: Event type, event parameter, and event result.

ResumeCallback

Callback function for obtaining the resumable upload control parameters.

NOTE:
  • The callback function contains the following parameters: the control parameter for canceling the resumable upload task and the resumable upload record object.
  • You can invoke the cancel method of the control parameter for canceling the resumable upload task to suspend a resumable upload task.
Sample code: 
// Create an instance of ObsClient.
var obsClient = new ObsClient({
    access_key_id: '*** Provide your Access Key ***',       
    secret_access_key: '*** Provide your Secret Key ***',       
    server : 'https://your-endpoint'
});

var cp;
var hook;
obsClient.uploadFile({
       Bucket : 'bucketname',
       Key : 'objectname',
       SourceFile : document.getElementById('input-file').files[0],
       PartSize : 9 * 1024 * 1024,
       ProgressCallback : function(transferredAmount, totalAmount, totalSeconds){
           console.log(transferredAmount * 1.0 / totalSeconds / 1024);
           console.log(transferredAmount * 100.0 / totalAmount);
           if(hook && (transferredAmount / totalAmount) > 0.5){
                // Suspend a resumable download task.
               hook.cancel();
           }
       },
       EventCallback : function(eventType, eventParam, eventResult){
           // Handle event response.
       },
       ResumeCallback : function(resumeHook, uploadCheckpoint){
           // Obtain the control parameters for canceling resumable upload.
           hook = resumeHook;
           // Record a breakpoint.
           cp = uploadCheckpoint;
       }
}, function(err, result){
    console.error('Error-->' + err);
    // If an error occurs, call the resumable upload API again to continue the upload task.
    if(err){
       obsClient.uploadFile({
          UploadCheckpoint : cp,
          ProgressCallback : function(transferredAmount, totalAmount, totalSeconds){
              console.log(transferredAmount * 1.0 / totalSeconds / 1024);
              console.log(transferredAmount * 100.0 / totalAmount);
          },
          EventCallback : function(eventType, eventParam, eventResult){
           // Handle event response.
          },
        }, function(err, result){
          if(err){
              console.error('Error-->' + err);
          }else{
              if(result.CommonMsg.Status < 300){
                 console.log('RequestId-->' + result.InterfaceResult.RequestId);
                 console.log('Bucket-->' + result.InterfaceResult.Bucket);
                 console.log('Key-->' + result.InterfaceResult.Key);
                 console.log('Location-->' + result.InterfaceResult.Location);
              }else{
                 console.log('Code-->' + result.CommonMsg.Code);
                 console.log('Message-->' + result.CommonMsg.Message);
              }
        }
      });
    }else {
         console.log('Status-->' + result.CommonMsg.Status);
         if (result.CommonMsg.Status < 300 && result.InterfaceResult) {
                console.log('RequestId-->' + result.InterfaceResult.RequestId);
         }
    }
});
  • The API for resumable upload, which is implemented based on multipart upload, is an encapsulated and enhanced version of multipart upload.
  • The breakpoint record object can be obtained through ResumeCallback. The sourceFile field in the resumable upload record object indicates the file to be uploaded. This field needs to be set again after the browser is restarted.
Parent topic: Object Upload