I’m working on an Angular application and need to generate an MD5 checksum for a file. I found that the SparkMD5 library can be used for this purpose, but I’m not sure how to integrate it into my Angular project.
Could someone provide a step-by-step guide or example on how to achieve this?
<code>onFileSelected(event: any) {
const file = event.target.files[0];
if (file) {
this.computeMD5(file);
}
}
computeMD5(file: File) {
const fileReader = new FileReader();
fileReader.onload = (e) => {
const arrayBuffer: ArrayBuffer = e.target?.result as ArrayBuffer;
const md5 = SparkMD5.ArrayBuffer.hash(arrayBuffer);
this.fileChecksum = md5;
};
fileReader.readAsArrayBuffer(file);
}
computeChecksumMd5(file: File): Promise<string> {
return new Promise((resolve, reject) => {
const chunkSize = 2097152; // Read in chunks of 2MB
const spark = new SparkMD5.ArrayBuffer();
const fileReader = new FileReader();
let cursor = 0; // current cursor in file
fileReader.onerror = function(): void {
reject('MD5 computation failed - error reading the file');
};
// read chunk starting at `cursor` into memory
function processChunk(chunk_start: number): void {
const chunk_end = Math.min(file.size, chunk_start + chunkSize);
fileReader.readAsArrayBuffer(file.slice(chunk_start, chunk_end));
}
// when it's available in memory, process it
// If using TS >= 3.6, you can use `FileReaderProgressEvent` type instead
// of `any` for `e` variable, otherwise stick with `any`
// See https://github.com/Microsoft/TypeScript/issues/25510
fileReader.onload = function(e: any): void {
spark.append(e.target.result); // Accumulate chunk to md5 computation
cursor += chunkSize; // Move past this chunk
if (cursor < file.size) {
// Enqueue next chunk to be accumulated
processChunk(cursor);
} else {
// Computation ended, last chunk has been processed. Return as Promise value.
// This returns the base64 encoded md5 hash, which is what
// Rails ActiveStorage or cloud services expect
resolve(btoa(spark.end(true)));
// If you prefer the hexdigest form (looking like
// '7cf530335b8547945f1a48880bc421b2'), replace the above line with:
// resolve(spark.end());
}
};
processChunk(0);
});
}
</code>
<code>onFileSelected(event: any) {
const file = event.target.files[0];
if (file) {
this.computeMD5(file);
}
}
computeMD5(file: File) {
const fileReader = new FileReader();
fileReader.onload = (e) => {
const arrayBuffer: ArrayBuffer = e.target?.result as ArrayBuffer;
const md5 = SparkMD5.ArrayBuffer.hash(arrayBuffer);
this.fileChecksum = md5;
};
fileReader.readAsArrayBuffer(file);
}
computeChecksumMd5(file: File): Promise<string> {
return new Promise((resolve, reject) => {
const chunkSize = 2097152; // Read in chunks of 2MB
const spark = new SparkMD5.ArrayBuffer();
const fileReader = new FileReader();
let cursor = 0; // current cursor in file
fileReader.onerror = function(): void {
reject('MD5 computation failed - error reading the file');
};
// read chunk starting at `cursor` into memory
function processChunk(chunk_start: number): void {
const chunk_end = Math.min(file.size, chunk_start + chunkSize);
fileReader.readAsArrayBuffer(file.slice(chunk_start, chunk_end));
}
// when it's available in memory, process it
// If using TS >= 3.6, you can use `FileReaderProgressEvent` type instead
// of `any` for `e` variable, otherwise stick with `any`
// See https://github.com/Microsoft/TypeScript/issues/25510
fileReader.onload = function(e: any): void {
spark.append(e.target.result); // Accumulate chunk to md5 computation
cursor += chunkSize; // Move past this chunk
if (cursor < file.size) {
// Enqueue next chunk to be accumulated
processChunk(cursor);
} else {
// Computation ended, last chunk has been processed. Return as Promise value.
// This returns the base64 encoded md5 hash, which is what
// Rails ActiveStorage or cloud services expect
resolve(btoa(spark.end(true)));
// If you prefer the hexdigest form (looking like
// '7cf530335b8547945f1a48880bc421b2'), replace the above line with:
// resolve(spark.end());
}
};
processChunk(0);
});
}
</code>
onFileSelected(event: any) {
const file = event.target.files[0];
if (file) {
this.computeMD5(file);
}
}
computeMD5(file: File) {
const fileReader = new FileReader();
fileReader.onload = (e) => {
const arrayBuffer: ArrayBuffer = e.target?.result as ArrayBuffer;
const md5 = SparkMD5.ArrayBuffer.hash(arrayBuffer);
this.fileChecksum = md5;
};
fileReader.readAsArrayBuffer(file);
}
computeChecksumMd5(file: File): Promise<string> {
return new Promise((resolve, reject) => {
const chunkSize = 2097152; // Read in chunks of 2MB
const spark = new SparkMD5.ArrayBuffer();
const fileReader = new FileReader();
let cursor = 0; // current cursor in file
fileReader.onerror = function(): void {
reject('MD5 computation failed - error reading the file');
};
// read chunk starting at `cursor` into memory
function processChunk(chunk_start: number): void {
const chunk_end = Math.min(file.size, chunk_start + chunkSize);
fileReader.readAsArrayBuffer(file.slice(chunk_start, chunk_end));
}
// when it's available in memory, process it
// If using TS >= 3.6, you can use `FileReaderProgressEvent` type instead
// of `any` for `e` variable, otherwise stick with `any`
// See https://github.com/Microsoft/TypeScript/issues/25510
fileReader.onload = function(e: any): void {
spark.append(e.target.result); // Accumulate chunk to md5 computation
cursor += chunkSize; // Move past this chunk
if (cursor < file.size) {
// Enqueue next chunk to be accumulated
processChunk(cursor);
} else {
// Computation ended, last chunk has been processed. Return as Promise value.
// This returns the base64 encoded md5 hash, which is what
// Rails ActiveStorage or cloud services expect
resolve(btoa(spark.end(true)));
// If you prefer the hexdigest form (looking like
// '7cf530335b8547945f1a48880bc421b2'), replace the above line with:
// resolve(spark.end());
}
};
processChunk(0);
});
}