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Author: javascript-2020

blog/25-07-31/fetch-download-stream/ex/ex.html

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+
+      <style>
+      </style>
+      
+      <div id=root>
+      
+            <div>
+                  encoding
+                  <span id=encoding></span>
+            </div>
+            <div>
+                  content-length
+                  <span id=content-length></span>
+            </div>
+            <div id=progress>
+                  <div id=bar></div>
+            </div>
+            
+      </div>
+
+
+      <script>
+
+(async()=>{
+console.clear();
+
+  
+        var url       = 'https://raw.githubusercontent.com/javascript-2020/external/main/ffmpeg/ffmpeg-wasm/ffmpeg-wasm.zip'
+        
+        
+        //var url   = 'https://cdn.jsdelivr.net/gh/javascript-2020/libs/js/io/tiny-unzip/tiny-unzip.m.js';
+        
+        var headers   = {};
+        var method    = 'get';
+        var body      = undefined;
+        
+        var res       = await fetch(url,{headers,method,body});
+        
+        var encoding    = res.headers.get('content-encoding')?.toLowerCase();
+        if(encoding && encoding!=='identity'){
+              console.log('unable to reliably computer content-length');
+        }
+        var len       = res.headers.get('content-length');
+        console.log(len);
+        var total     = 0;
+        var reader    = res.body.getReader();
+        var chunks    = [];
+        while(true){
+        
+              const {value,done}    = await reader.read();
+              if(done)break;
+                                                                                total  += value.length;
+                                                                                console.log('chunk',datatype(value),value.byteLength,total,(total/len*100).toFixed(1)+' %');
+              chunks.push(value);
+                                                                          
+        }//while
+        var total     = chunks.reduce((acc,chunk)=>acc+chunk.length,0);
+        var buf       = new Uint8Array(total);
+        var offset    = 0;
+        for(var chunk of chunks){
+                                            
+              buf.set(chunk,offset);
+              offset   += chunk.length;
+              
+        }//for
+        var blob    = new Blob([buf],{type:'application/octet-stream'});
+        console.log(blob);
+        
+        
+        
+        function datatype(v){return Object.prototype.toString.call(v).slice(8,-1).toLowerCase()}
+        
+})();
+
+
+      </script>