8 examples of 'convert blob to file' in JavaScript

76
export function file2Blob(file) {
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  return new Promise((resolve, reject) => {
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    var reader = new FileReader()
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    reader.readAsArrayBuffer(file)
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    reader.onload = function(e) {
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      resolve(new Blob([reader.result], { type: file.type }))
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    }
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    reader.onerror = function(err) {
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      reject(err)
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    }
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  })
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}

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function filenameForBlob( blob ) {
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	if ( blob.getName() ) {
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		return blob.getName()
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	}
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	const contentType = blob.getContentType()
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	if ( contentTypeToExtension[ contentType ] ) {
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		return DEFAULT_FILENAME + '.' + contentTypeToExtension[ contentType ]
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	}
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	throw new Error( 'Unsupported content type: ' + contentType )
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}

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function uploadFile(blobFile) {
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    var fd = new FormData();
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    fd.append(fileKey, blobFile, fileName);
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    for (var prop in params) {
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        if(params.hasOwnProperty(prop)) {
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            fd.append(prop, params[prop]);
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        }
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    }
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    xhr[fileKey].open("POST", server);
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    xhr[fileKey].onload = function(evt) {
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        if (xhr[fileKey].status === 200) {
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            var result = new FileUploadResult();
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            result.bytesSent = file.size;
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            result.responseCode = xhr[fileKey].status;
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            result.response = xhr[fileKey].response;
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            delete xhr[fileKey];
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            onSuccess(result);
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        } else if (xhr[fileKey].status === 404) {
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            onFail(new FileTransferError(FileTransferError.INVALID_URL_ERR, server, filePath, xhr[fileKey].status, xhr[fileKey].response));
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        } else {
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            onFail(new FileTransferError(FileTransferError.CONNECTION_ERR, server, filePath, xhr[fileKey].status, xhr[fileKey].response));
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        }
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    };
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    xhr[fileKey].ontimeout = function(evt) {
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        onFail(new FileTransferError(FileTransferError.CONNECTION_ERR, server, filePath, xhr[fileKey].status, xhr[fileKey].response));
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    };
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    xhr[fileKey].onerror = function () {
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        onFail(new FileTransferError(FileTransferError.CONNECTION_ERR, server, filePath, this.status, xhr[fileKey].response));
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    };
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    xhr[fileKey].upload.onprogress = function (evt) {
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        if (evt.loaded > 0) {
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            onSuccess(evt);
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        }
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    };
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    for (var header in headers) {
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        if (headers.hasOwnProperty(header)) {
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            xhr[fileKey].setRequestHeader(header, headers[header]);
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        }
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    }
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    requestAnimationFrame(function () {
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        xhr[fileKey].send(fd);
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    });
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}

68
function uploadFile(blobFile) {
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    var fd = new FormData();
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    fd.append(fileKey, blobFile, fileName);
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    for (var prop in params) {
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        if(params.hasOwnProperty(prop)) {
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            fd.append(prop, params[prop]);
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        }
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    }
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    xhr = new XMLHttpRequest();
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    xhr.open("POST", server);
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    xhr.onload = function(evt) {
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        if (xhr.status === 200) {
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            var result = new FileUploadResult();
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            result.bytesSent = file.size;
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            result.responseCode = xhr.status;
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            result.response = xhr.response;
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            win(result);
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        } else if (xhr.status === 404) {
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            fail(new FileTransferError(FileTransferError.INVALID_URL_ERR, server, filePath, xhr.status, xhr.response));
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        } else {
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            fail(new FileTransferError(FileTransferError.CONNECTION_ERR, server, filePath, xhr.status, xhr.response));
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        }
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    };
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    xhr.ontimeout = function(evt) {
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        fail(new FileTransferError(FileTransferError.CONNECTION_ERR, server, filePath, xhr.status, xhr.response));
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    };
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    xhr.onerror = function () {
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        fail(new FileTransferError(FileTransferError.CONNECTION_ERR, server, filePath, this.status, xhr.response));
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    };
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    xhr.onprogress = function (evt) {
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        win(evt);
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    };
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    for (var header in headers) {
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        if (headers.hasOwnProperty(header)) {
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            xhr.setRequestHeader(header, headers[header]);
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        }
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    }
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    xhr.send(fd);
110
}

33
async function mkBlobFile (blobRoot, ...pathPart) {
34
  pathPart.length > 1 && await mkBlobDir(blobRoot, ...pathPart.slice(0, pathPart.length - 1))
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  let fullPath = path.join(blobRoot, ...pathPart)
36
  return writeFile(fullPath, data)
37
}

13
export function blobToImage(blob) {
14
  return new Promise((resolve, reject) => {
15
    let url = URL.createObjectURL(blob);
16
    let image = new Image();
17
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    image.onload = () => {
19
      canvas.width = image.width;
20
      canvas.height = image.height;
21
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      ctx.drawImage(image, 0, 0);
23
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      resolve(image);
25
    };
26
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    image.onerror = (e) => {
28
      reject(e);
29
    };
30
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    image.src = url;
32
  });
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}

117
export function blob2ObjectURL(blobOrFile) {
118
  return URL && URL.createObjectURL
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    ? URL.createObjectURL(blobOrFile)
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    : new Error('blob2ObjectURL转换出错')
121
}

72
export async function blobToDataUrl(blob) {
73
  return new Promise((resolve, reject) => {
74
    const reader = new FileReader();
75
    reader.onload = event => {
76
      resolve(event.target.result);
77
    };
78
    reader.readAsDataURL(blob);
79
  });
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}