Changing a photo into base64 format using Angular 2

Question

Changing a photo into base64 format using Angular 2

How can I convert an image to base64 in Angular 2? The image is uploaded from the local filesystem. Currently, I am using fileLoadedEvent.target.result to achieve this. However, when I try to send this base64 string through REST services to Java, it fails to decode. Even when I use free online encoder-decoder tools, I am unable to see the decoded image. I have also attempted using canvas but without success. It seems that the base64 string generated is not proper. Do I need to add any specific package for this task in Angular 2? Or is there a particular method to encode images to base64 as seen in Angular 1 with the angular-base64-upload package?

Below is a snippet of my code:


onFileChangeEncodeImageFileAsURL(event:any,imgLogoUpload:any,imageForLogo:any,imageDiv:any)
{
    var filesSelected = imgLogoUpload.files;
    var self = this;
    if (filesSelected.length > 0) {
      var fileToLoad = filesSelected[0]; 

      //Reading Image file, encode and display
       var  reader: FileReader = new FileReader();
       reader.onloadend = function(fileLoadedEvent:any) {

       //SECOND METHO
       var imgSrcData = fileLoadedEvent.target.result; // <--- data: base64 

        var newImage = imageForLogo;
        newImage.src = imgSrcData;
        imageDiv.innerHTML = newImage.outerHTML;

      }
      reader.readAsDataURL(fileToLoad);
    }
}

javascript java jquery angular typescript

Answer 1

Answer №1

Functional plunkr demonstrating base64 string conversion

Check out the working example here!

  handleFileSelect(evt){
      var files = evt.target.files;
      var file = files[0];

    if (files && file) {
        var reader = new FileReader();

        reader.onload =this._handleReaderLoaded.bind(this);

        reader.readAsBinaryString(file);
    }
  }



  _handleReaderLoaded(readerEvt) {
     var binaryString = readerEvt.target.result;
            this.base64textString= btoa(binaryString);
            console.log(btoa(binaryString));
    }

Answer 2

Functional plunkr demonstrating base64 string conversion

Check out the working example here!

  handleFileSelect(evt){
      var files = evt.target.files;
      var file = files[0];

    if (files && file) {
        var reader = new FileReader();

        reader.onload =this._handleReaderLoaded.bind(this);

        reader.readAsBinaryString(file);
    }
  }



  _handleReaderLoaded(readerEvt) {
     var binaryString = readerEvt.target.result;
            this.base64textString= btoa(binaryString);
            console.log(btoa(binaryString));
    }

Answer 3

Answer №2

I made some modifications to Parth Ghiya's solution, allowing you to upload multiple images which are then stored in an array as base64 encoded strings.

base64textString = [];

onUploadChange(evt: any) {
  const file = evt.target.files[0];

  if (file) {
    const reader = new FileReader();

    reader.onload = this.handleReaderLoaded.bind(this);
    reader.readAsBinaryString(file);
  }
}

handleReaderLoaded(e) {
  this.base64textString.push('data:image/png;base64,' + btoa(e.target.result));
}

Include the following code in your HTML file:

<input type="file" (change)="onUploadChange($event)" accept=".png, .jpg, .jpeg, .pdf" />
<img *ngFor="let item of base64textString" src={{item}} alt="" id="img">

Answer 4

I made some modifications to Parth Ghiya's solution, allowing you to upload multiple images which are then stored in an array as base64 encoded strings.

base64textString = [];

onUploadChange(evt: any) {
  const file = evt.target.files[0];

  if (file) {
    const reader = new FileReader();

    reader.onload = this.handleReaderLoaded.bind(this);
    reader.readAsBinaryString(file);
  }
}

handleReaderLoaded(e) {
  this.base64textString.push('data:image/png;base64,' + btoa(e.target.result));
}

Include the following code in your HTML file:

<input type="file" (change)="onUploadChange($event)" accept=".png, .jpg, .jpeg, .pdf" />
<img *ngFor="let item of base64textString" src={{item}} alt="" id="img">

Answer 5

Answer №3

Here is another approach that works for base64 encoding, as discussed in this post:

In my scenario, I implemented the following:

getImagem(readerEvt, midia){
    //console.log('change no input file', readerEvt);
    let file = readerEvt.target.files[0];
    var reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = function () {
        //console.log('base64 do arquivo',reader.result);
        midia.binario = btoa(reader.result);
        //console.log('base64 do arquivo codificado',midia.binario);
    };
    reader.onerror = function (error) {
        console.log('Erro ao ler a imagem : ', error);
    };
}

Additionally, I used the following HTML components:

<input type="file" class="form-control"  (change)="getImagem($event, imagem)">

<img class="img-responsive"  src="{{imagem.binario | decode64 }}" alt="imagem..." style="width: 200px;"/>

To render the image properly, I created a custom pipe called decode64:

@Pipe({
  name: 'decode64'
})
export class Decode64Pipe implements PipeTransform {
  transform(value: any, args?: any): any {
    let decodedValue = '';
    if(value){
       decodedValue = atob(value);
    }
    return decodedValue;
  }
}

Answer 6

Here is another approach that works for base64 encoding, as discussed in this post:

In my scenario, I implemented the following:

getImagem(readerEvt, midia){
    //console.log('change no input file', readerEvt);
    let file = readerEvt.target.files[0];
    var reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = function () {
        //console.log('base64 do arquivo',reader.result);
        midia.binario = btoa(reader.result);
        //console.log('base64 do arquivo codificado',midia.binario);
    };
    reader.onerror = function (error) {
        console.log('Erro ao ler a imagem : ', error);
    };
}

Additionally, I used the following HTML components:

<input type="file" class="form-control"  (change)="getImagem($event, imagem)">

<img class="img-responsive"  src="{{imagem.binario | decode64 }}" alt="imagem..." style="width: 200px;"/>

To render the image properly, I created a custom pipe called decode64:

@Pipe({
  name: 'decode64'
})
export class Decode64Pipe implements PipeTransform {
  transform(value: any, args?: any): any {
    let decodedValue = '';
    if(value){
       decodedValue = atob(value);
    }
    return decodedValue;
  }
}

Answer 7

Answer №4

If you're looking to encode an image to base64, have you considered using btoa or Crypto.js?

For more information on Crypto.js, you can visit their website here: https://code.google.com/archive/p/crypto-js/

You can use window.btoa(fileLoadedEvent.target.result) to encode the image.

Alternatively, you can try using

CryptoJS.enc.Base64.stringify(fileLoadedEvent.target.result)

.

Answer 8

If you're looking to encode an image to base64, have you considered using btoa or Crypto.js?

For more information on Crypto.js, you can visit their website here: https://code.google.com/archive/p/crypto-js/

You can use window.btoa(fileLoadedEvent.target.result) to encode the image.

Alternatively, you can try using

CryptoJS.enc.Base64.stringify(fileLoadedEvent.target.result)

.

Answer 9

Answer №5

Take a look at the following code snippet by Parth Ghiya, now transformed into ES6/TypeScript:

image: string;
handleFileUpload(evt){
    const file = evt.target.files[0];
    if (!file) {
        return false;
    }
    const reader = new FileReader();
    
    reader.onload = () => {
        this.image = reader.result as string;
    };

    console.log(btoa(this.image));
}

Answer 10

Take a look at the following code snippet by Parth Ghiya, now transformed into ES6/TypeScript:

image: string;
handleFileUpload(evt){
    const file = evt.target.files[0];
    if (!file) {
        return false;
    }
    const reader = new FileReader();
    
    reader.onload = () => {
        this.image = reader.result as string;
    };

    console.log(btoa(this.image));
}

Answer 11

Answer №6

After much consideration, I have devised a solution involving the use of an HTTP request for sending data in JSON format.

Here are some key points to note:
1. The event parameter is sourced from an HTML input tag.
2. `self.imageSrc` serves as a component variable for storing data. To access this data in the header file, it is necessary to convert "this" to a self variable and utilize it within the onLoad function.
3. `this.server` pertains to the API calling service component variable used within this particular component.

UploadImages(event) {
    var file = event.target.files[0];
    var reader = new FileReader();
    reader.readAsDataURL(file);
    var self = this;
    reader.onload = function() {
      self.imageSrc = reader.result.toString();
    };

    var image_data = {
      authentication_token: this.UD.getAuth_key ,
      fileToUpload: this.imageSrc,
      attachable_type: "Photo"
    };

    this.server.photo_Upload(image_data).subscribe(response => {
      if (response["success"]) {
        console.log(response);
      } else {
        console.log(response);
      }
    });
  }

Answer 12

After much consideration, I have devised a solution involving the use of an HTTP request for sending data in JSON format.

Here are some key points to note:
1. The event parameter is sourced from an HTML input tag.
2. `self.imageSrc` serves as a component variable for storing data. To access this data in the header file, it is necessary to convert "this" to a self variable and utilize it within the onLoad function.
3. `this.server` pertains to the API calling service component variable used within this particular component.

UploadImages(event) {
    var file = event.target.files[0];
    var reader = new FileReader();
    reader.readAsDataURL(file);
    var self = this;
    reader.onload = function() {
      self.imageSrc = reader.result.toString();
    };

    var image_data = {
      authentication_token: this.UD.getAuth_key ,
      fileToUpload: this.imageSrc,
      attachable_type: "Photo"
    };

    this.server.photo_Upload(image_data).subscribe(response => {
      if (response["success"]) {
        console.log(response);
      } else {
        console.log(response);
      }
    });
  }

Answer 13

Answer №7

I highly recommend utilizing the following package for converting images to base64: image-to-base64

You can easily generate a base64 image by providing either a path or URL.

Another great resource is this accepted answer on Stack Overflow

Answer 14

I highly recommend utilizing the following package for converting images to base64: image-to-base64

You can easily generate a base64 image by providing either a path or URL.

Another great resource is this accepted answer on Stack Overflow

Changing a photo into base64 format using Angular 2

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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