SQCloudDownloadDatabase

bool SQCloudDownloadDatabase (SQCloudConnection *connection, const char *dbname, void *xdata,
                              int (*xCallback)(void *xdata, const void *buffer, uint32_t blen, int64_t ntot, int64_t nprogress));

Description

Initiate an SQLite database download from an already connected SQLite Cloud node.

Parameters

• connection: a valid connection object obtained by SQCloudConnect or SQCloudConnectWithString
• dbname: the name of the database to download
• xdata: a pointer to an opaque datatype that will be passed as-is to the callback
• xcallback: callback that will be automatically called to read from the input database file

Return value

true if download is succesfully completed.

Example

#define DATABASE_PATH "/full_path_to/database.sqlite"

// convenient struct to be used with SQCloudDownloadDatabase
typedef struct {
    void            *ptr;
    int             fd;
} SQCloudData;

static int do_internal_download_cb (void *xdata, const void *buffer, uint32_t blen, int64_t ntot, int64_t nprogress) {
    if (blen) {
        // retrieve file descriptor
        int fd = ((SQCloudData *)xdata)->fd;

        // write data
        if (write(fd, buffer, (size_t)blen) != blen) {
            printf("\nError while writing data to file.\n");
            return -1;
        }
    }
    
    // display a simple text progress
    printf("%.2f%% ", ((double)nprogress / (double)ntot) * 100.0);
    
    // check if it is final step
    if (ntot == nprogress) printf("\n\n");
    
    // means no error and continue the loop
    return 0;
}

int main (int argc, const char * argv[]) {
    // setup config
    SQCloudConfig config = {0};
    config.username = "myusername";
    config.password = "mypassword"

    SQCloudConnection *conn = SQCloudConnect("myproject.sqlite.cloud", SQCLOUD_DEFAULT_PORT, &config);
    if (SQCloudIsError(conn)) {
        printf("ERROR connecting: %s (%d)\n", SQCloudErrorMsg(conn), SQCloudErrorCode(conn));
        return -1;
    } else {
        printf("Connection to host OK...\n\n");
    }

    // create file
    int fd = file_create(DATABASE_PATH);
    if (fd < 0) {
        printf("Unable to create output file %s\n", DATABASE_PATH);
        return false;
    }
    
    SQCloudData data = {.ptr = NULL, .fd = fd};
    bool result = SQCloudDownloadDatabase(conn, "database.sqlite", (void *)&data, do_internal_download_cb);
    if (!result) {
        // handle error here
    }
    
    close(fd);
}