Zig

The MIME Content-Type Header Field

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Explains the ContentType property and the Content-Type header field including the various attributes that may be included. Zig

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

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

    // Every part in a MIME messsage should include a Content-Type header field.
    // The Content-Type indicates the type of content contained in the MIME part.
    // For example: text/plain, image/jpeg, application/pdf, application/json, multipart/mixed, etc.

    // Multipart content types are those where the MIME part's body is composed of N inner MIME messages,
    // separated by a boundary string.
    // This is how MIME gets a nested, tree-like structure.  The most common multipart MIME types
    // are (for email related MIME) multipart/mixed, multipart/alternative, and multipart/related,
    // and for HTTP related MIME, it is multipart/form-data.

    const mime = try chilkat.Mime.init();
    defer mime.deinit();

    // The Content-Type header field can be set or modified in two ways.
    // 1) By setting the ContentType, Micalg, Name, Charset, Boundary, or Protocol properties.
    //    Setting the ContentType property sets the primary value (such as "text/plain") of the header field.
    //    Each of the other properties listed above will replace or add a particular attribute value.

    // 2) By setting the entire contents of the ContentType header with the SetHeaderField method.
    //    This updates each of the Content-Type related properties.

    // For example:
    mime.setContentType("text/plain");
    mime.setCharset("utf-8");

    // The Content-Type header field contains this:
    //     Content-Type: text/plain; charset=utf-8
    std.debug.print("{s}\n", .{try mime.getEntireHead(alloc)});
    std.debug.print("-\n", .{});

    mime.setHeaderField("Content-Type", "image/jpeg; name=\"kitty.jpg\"") catch {};
    // The Content-Type header field now contains this:
    //     Content-Type: image/jpeg; name="kitty.jpg"
    std.debug.print("{s}\n", .{try mime.getEntireHead(alloc)});
    std.debug.print("-\n", .{});

    // Notice how the properties have been updated:
    std.debug.print("ContentType property: {s}\n", .{try mime.getContentType(alloc)});
    std.debug.print("Charset property: {s}\n", .{try mime.getCharset(alloc)});
    std.debug.print("Name property: {s}\n", .{try mime.getName(alloc)});
    std.debug.print("-\n", .{});

    // To change a particular attribute value, set the property.
    mime.setName("doggy.jpg");
    std.debug.print("{s}\n", .{try mime.getEntireHead(alloc)});
    std.debug.print("-\n", .{});

    // To remove an attribute value from the Content-Type header,
    // set the property to an empty string.
    mime.setName("");
    std.debug.print("{s}\n", .{try mime.getEntireHead(alloc)});
    std.debug.print("-\n", .{});
}