B4R Tutorial ESP32: Download huge file from a server and save it

This example downloads a file from a server folder (here I use a folder in htdocs on my apache server) and saves it to a file on the file system. Tested with 700KB files. Set headers (browse the www how to set up headers or credentials). Note that the ESP32 filesystem is quite slow. Downloading 700 KB is quite fast, but writing to a file not.

Any file type will do (binary, text, etc.)

Used libs:

#Region Project Attributes
    #AutoFlushLogs: True
    #CheckArrayBounds: True
    #StackBufferSize: 10000
#End Region

Sub Process_Globals
    Public Serial1 As Serial
    Private fs As ESP8266FileSystem
    Private wifi As ESP8266WiFi
    Private bc As ByteConverter
    Private FullPath(200) As Byte
    Private SaveAs(40) As Byte
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("AppStart")
   
    For i=1 To 10
        Log("Connecting to WiFi...")
        Log(i)
       
        If wifi.Connect2("SSID","PW") Then
            Log("Connected to wireless network.")
            Log("My ip: ", wifi.LocalIp)
            InitFS
            DownloadFile
            ListFiles
            Exit
        Else
            Log("Failed to connect...")
        End If
    Next
   
End Sub

Sub DownloadFile
    bc.ArrayCopy("http://192.168.178.23/somefolder/somefile.txt",FullPath)
    bc.ArrayCopy("/somefilenew.txt",SaveAs) '/ is important!
    RunNative("downloadfile", Null)
End Sub

Sub InitFS
    Log("Initializing Filesystem...")
   
    If(fs.Initialize())=False Then
        Log("Formatting Filesystem. This may take some time")
        fs.Format
        If(fs.Initialize())=True Then
            Log("Formatting succesful...")
           
        Else
            Log("Error formatting Filesystem...")
        End If
    End If
   
    Log("Total size: ", NumberFormat(fs.TotalSize / 1024, 0, 0), " KB")
    Log("Used size: ", NumberFormat(fs.UsedSize / 1024, 0, 0), " KB")
    ListFiles
End Sub

Sub ListFiles
    Log("Files:")
    For Each f As File In fs.ListFiles("/")
        Log("     ",f.Name," Size: ",f.Size)
    Next
End Sub



#if c
#include <HTTPClient.h>
#include "FS.h"
#include "SPIFFS.h"
void downloadfile(B4R::Object* o) {
   
    HTTPClient http;

    printf("Downloading from %s...\n",(char*)b4r_main::_fullpath->data);
    printf("Saving as %s...\n",(char*)b4r_main::_saveas->data);
   
    // configure server and url
    http.begin((char*)b4r_main::_fullpath->data);

    printf("[HTTP] GET...\n");
    // start connection and send HTTP header
    int httpCode = http.GET();
    if(httpCode > 0) {
        // HTTP header has been send and Server response header has been handled
        // file found at server
        if(httpCode == HTTP_CODE_OK) {
            printf("Connected...\n");
            // get lenght of document (is -1 when Server sends no Content-Length header)
            int len = http.getSize();
            printf("Filesize is %i\n", len);
            // create buffer for read
            uint8_t buff[1024] = { 0 };

            // get tcp stream
            WiFiClient * stream = http.getStreamPtr();
           
            //File
           
            File file = SPIFFS.open((char*)b4r_main::_saveas->data, "w");
            if(!file){
                Serial.println("- failed to open file for writing");
                return;
            }
            printf("Writing File...\n");
            //File
            int total=0;
            // read all data from server
            while(http.connected() && (len > 0 || len == -1)) {
                // get available data size
                size_t size = stream->available();
               
                if(size) {
                    // read up to (buffer size) bytes
                    int c = stream->readBytes(buff, ((size > sizeof(buff)) ? sizeof(buff) : size));
                                       
                    //file.print((char *)buff);
                    file.write((byte*) &buff, c);
                    total=total+ c;      
                    //File

                    if(len > 0) {
                        len -= c;
                    }
                }
                delay(1);
            }
            file.close();
            printf("Total Bytes downloaded: %i\n", total);
        }
    } else {
        printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str());
    }

    http.end();
}

#End If