Zig

Pre-Allocate Server Space Before an FTP Upload (ALLO)

Demonstrates the AllocateSize property, which sends the FTP ALLO command to pre-allocate disk space on the server before an upload. Set it to the size in bytes of the file about to be uploaded.

Background: ALLO asks the server to reserve storage in advance, a requirement of certain legacy systems — older mainframes in particular — that need the exact file size up front to allocate a dataset. Modern servers allocate space dynamically and typically ignore or accept ALLO without needing it, so most applications never set this. Provide it only when targeting a host known to require pre-allocation.

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Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    const ftp = try chilkat.Ftp2.init();
    defer ftp.deinit();

    ftp.setHostname("ftp.example.com");
    ftp.setUsername("myFtpLogin");

    // Normally you would not hard-code the password in source.  You should instead obtain it
    // from an interactive prompt, environment variable, or a secrets vault.
    ftp.setPassword("myPassword");

    ftp.connect() catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };

    // AllocateSize sends the FTP ALLO command to pre-allocate disk space on the server before an
    // upload.  It is rarely needed -- mainly for certain legacy systems that require the exact size
    // in advance -- since most servers allocate space dynamically.  Set it to the size in bytes of
    // the file about to be uploaded.
ERROR: Assignment type mismatch.  ExpressionType=int, atgType=uint

    ftp.putFile("qa_data/bigfile.zip", "uploads/bigfile.zip") catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("Uploaded with pre-allocation.\n", .{});

    ftp.disconnect() catch {
        std.debug.print("{s}\n", .{try ftp.getLastErrorText(alloc)});
        return;
    };
}