the mySql blob class has the following function : blob.getBytes use it like this: //(assuming you have a ResultSet named RS) Blob blob = rs.getBlob(“SomeDatabaseField”); int blobLength = (int) blob.length(); byte[] blobAsBytes = blob.getBytes(1, blobLength); //release the blob and free up memory. (since JDBC 4.0) blob.free();
Blobs are returned with file type from backend. The following function will accept any file type and popup download window: downloadFile(route: string, filename: string = null): void{ const baseUrl=”http://myserver/index.php/api”; const token = ‘my JWT’; const headers = new HttpHeaders().set(‘authorization’,’Bearer ‘+token); this.http.get(baseUrl + route,{headers, responseType: ‘blob’ as ‘json’}).subscribe( (response: any) =>{ let dataType = response.type; let … Read more
TEXT and CHAR will convert to/from the character set they have associated with time. BLOB and BINARY simply store bytes. BLOB is used for storing binary data while Text is used to store large string. BLOB values are treated as binary strings (byte strings). They have no character set, and sorting and comparison are based … Read more
You can read large blobs in pieces. First find out which ones need this treatment: SELECT id, length(blobcolumn) FROM mytable WHERE length(blobcolumn) > 1000000 and then read chunks with substr: SELECT substr(blobcolumn, 1, 1000000) FROM mytable WHERE id = 123 SELECT substr(blobcolumn, 1000001, 1000000) FROM mytable WHERE id = 123 … You could also compile … Read more
The existing answer appears largely out of date. Chrome (57+ it appears): According to Chrome’s Blob Storage System Design: Blob Storage Limits We calculate the storage limits here. In-Memory Storage Limit If the architecture is x64 and NOT ChromeOS or Android: 2GB Otherwise: total_physical_memory / 5 Disk Storage Limit If ChromeOS: disk_size / 2 If … Read more
BLOB : BLOB (Binary Large Object) is a large object data type in the database system. BLOB could store a large chunk of data, document types and even media files like audio or video files. BLOB fields allocate space only whenever the content in the field is utilized. BLOB allocates spaces in Giga Bytes. USAGE … Read more
Came across this SO trying to figure out how to download a png image and found that the other answer didn’t quite do it for me as the downloaded file couldn’t be opened. Needed to use arraybuffer to convert the image. Here’s the code that worked. function App() { const download = e => { … Read more
To answer parts of your question: How do clients go with caching images from the DB vs from the filesystem? For a database: Have a last_modified field in your database. Use the Last-Modified HTTP header so the client’s browser can cache properly. Be sure to send the appropriate responses when the browser requests for an … Read more
Your best option is to use a blob url (which is a special url that points to an object in the browser’s memory) : var myBlob = …; var blobUrl = URL.createObjectURL(myBlob); Now you have the choice to simply redirect to this url (window.location.replace(blobUrl)), or to create a link to it. The second solution allows … Read more
You have to understand how media files are built. It is not only some raw data that can be converted to either audio or video directly. It will depend on the format chosen, but the basic case is that you have what is called metadata which are like a dictionary describing how the file is … Read more