Zig

Upload File in Blocks and Commit the Block List

See more Azure Cloud Storage Examples

Demonstrates how to upload a file in blocks and then commit the block list. For files larger than 64MB, this is the way to upload to Azure Storage. Azure limits the size of each block to a maximum of 4MB. Zig

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

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

    // Azure Blob Service Example: Upload a file in blocks, and then commit the block list.
    // See also: https://msdn.microsoft.com/en-us/library/azure/dd135726.aspx

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    const rest = try chilkat.Rest.init();
    defer rest.deinit();

    // Connect to the Azure Storage Blob Service
    const b_tls = true;
    const port = 443;
    const b_auto_reconnect = true;
    // In this example, the storage account name is "chilkat".
    rest.connect("chilkat.blob.core.windows.net", port, b_tls, b_auto_reconnect) catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // Provide Azure Cloud credentials for the REST call.
    const az_auth = try chilkat.AuthAzureStorage.init();
    defer az_auth.deinit();
    az_auth.setAccessKey("AZURE_ACCESS_KEY");
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    az_auth.setAccount("chilkat");
    az_auth.setScheme("SharedKey");
    az_auth.setService("Blob");
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    az_auth.setXMsVersion("2021-08-06");
    try rest.setAuthAzureStorage(az_auth);

    // Note: The application does not need to explicitly set the following
    // headers: Content-Length, x-ms-date, Authorization.  These headers
    // are automatically set by Chilkat.

    // As the blocks are uploaded, we'll keep an XML block list for the subsequent commit..
    const xml = try chilkat.Xml.init();
    defer xml.deinit();
    xml.setTag("BlockList");

    // Any type of file can be uploaded in this way.  It can a text file, binary file, anything...
    // This example will upload an XML file that is approximately 275K in size.  It can be downloaded
    // at http://www.chilkatsoft.com/hamlet.xml
    const fac = try chilkat.FileAccess.init();
    defer fac.deinit();
    try fac.openForRead("qa_data/xml/hamlet.xml");
    // Assuming success for the example..

    // We'll upload in 16K blocks (normally a program would upload in larger block sizes than this,
    // but this is just an example...)
    const block_size = 16384;

    // How many 16K blocks?  (Including 1 for the last partial block)
    const num_blocks = fac.getNumBlocks(block_size);

    const sb_response_body = try chilkat.StringBuilder.init();
    defer sb_response_body.deinit();
    const uri_path = try chilkat.StringBuilder.init();
    defer uri_path.deinit();
    var block_id: [:0]const u8 = "";
    const data_block = try chilkat.BinData.init();
    defer data_block.deinit();
    var i: i32 = 0;
    while (i < num_blocks) {
        data_block.clear() catch {};
        fac.readBlockBd(i, block_size, data_block) catch {
            std.debug.print("{s}\n", .{try fac.getLastErrorText(alloc)});
            return;
        };

        // Generate a base64 block ID.
        // (Chilkat provides a helper method named GenBlockId to make this easy)
        // A pre-base64 encoded block ID length of 4 is sufficient in this case because
        // this file certainly won't have more than 99,999 blocks..
        block_id = try fac.genBlockId(alloc, i, 4, "base64");

        // Add this blockId to the list of blocks to be committed.
        xml.newChild2("Latest", block_id);

        // Build the URI path
        uri_path.clear();
        try uri_path.append("/mycontainer/hamlet.xml?comp=block&blockId=");
        try uri_path.append(block_id);

        // Upload this block..
        sb_response_body.clear();
        rest.fullRequestBd("PUT", try uri_path.getAsString(alloc), data_block, sb_response_body) catch {
            std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
            return;
        };

        // Verify that we received a 201 status code.
        if (rest.getResponseStatusCode() != 201) {
            // Examine the request/response to see what happened.
            std.debug.print("response status code = {d}\n", .{rest.getResponseStatusCode()});
            std.debug.print("response status text = {s}\n", .{try rest.getResponseStatusText(alloc)});
            std.debug.print("response header: {s}\n", .{try rest.getResponseHeader(alloc)});
            std.debug.print("response body (if any): {s}\n", .{try sb_response_body.getAsString(alloc)});
            std.debug.print("---\n", .{});
            std.debug.print("LastRequestStartLine: {s}\n", .{try rest.getLastRequestStartLine(alloc)});
            std.debug.print("LastRequestHeader: {s}\n", .{try rest.getLastRequestHeader(alloc)});
            return;
        }

        i = i + 1;
    }

    fac.fileClose();

    // Now commit the blocks.
    // Let's have a look at the XML that will commit the blocks:
    const xml_str = try xml.getXml(alloc);
    std.debug.print("{s}\n", .{xml_str});

    // The XML will look like this:

    // <?xml version="1.0" encoding="utf-8" ?>
    // <BlockList>
    //     <Latest>MDAwMA==</Latest>
    //     <Latest>MDAwMQ==</Latest>
    //     <Latest>MDAwMg==</Latest>
    //     <Latest>MDAwMw==</Latest>
    //     <Latest>MDAwNA==</Latest>
    //     <Latest>MDAwNQ==</Latest>
    //     <Latest>MDAwNg==</Latest>
    //     <Latest>MDAwNw==</Latest>
    //     <Latest>MDAwOA==</Latest>
    //     <Latest>MDAwOQ==</Latest>
    //     <Latest>MDAxMA==</Latest>
    //     <Latest>MDAxMQ==</Latest>
    //     <Latest>MDAxMg==</Latest>
    //     <Latest>MDAxMw==</Latest>
    //     <Latest>MDAxNA==</Latest>
    //     <Latest>MDAxNQ==</Latest>
    //     <Latest>MDAxNg==</Latest>
    //     <Latest>MDAxNw==</Latest>
    // </BlockList>

    // Send the PUT Block List...
    const response_str = rest.fullRequestString(alloc, "PUT", "/mycontainer/hamlet.xml?comp=blocklist", xml_str) catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // When successful, the Azure Storage service will respond with a 201 response status code,
    // with no response body.

    if (rest.getResponseStatusCode() != 201) {
        // Examine the request/response to see what happened.
        std.debug.print("response status code = {d}\n", .{rest.getResponseStatusCode()});
        std.debug.print("response status text = {s}\n", .{try rest.getResponseStatusText(alloc)});
        std.debug.print("response header: {s}\n", .{try rest.getResponseHeader(alloc)});
        std.debug.print("response body (if any): {s}\n", .{response_str});
        std.debug.print("---\n", .{});
        std.debug.print("LastRequestStartLine: {s}\n", .{try rest.getLastRequestStartLine(alloc)});
        std.debug.print("LastRequestHeader: {s}\n", .{try rest.getLastRequestHeader(alloc)});
        return;
    }

    std.debug.print("Success.\n", .{});
}