Zig

DynamoDB - DeleteItem

See more Amazon DynamoDB Examples

Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value. Zig

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

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

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

    // Implements the following CURL command:

    // curl -X POST https://dynamodb.us-west-2.amazonaws.com/ \
    //   -H "Accept-Encoding: identity" \
    //   -H "Content-Type: application/x-amz-json-1.0" \
    //   -H "Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature>" \
    //   -H "X-Amz-Date: <Date>" \
    //   -H "X-Amz-Target: DynamoDB_20120810.DeleteItem" \
    //   -d '{
    //     "TableName": "Thread",
    //     "Key": {
    //         "ForumName": {
    //             "S": "Amazon DynamoDB"
    //         },
    //         "Subject": {
    //             "S": "How do I update multiple items?"
    //         }
    //     },
    //     "ConditionExpression": "attribute_not_exists(Replies)",
    //     "ReturnValues": "ALL_OLD"
    // }'

    // Use the following online tool to generate REST code from a CURL command
    // Convert a cURL Command to REST Source Code

    const auth_aws = try chilkat.AuthAws.init();
    defer auth_aws.deinit();
    auth_aws.setAccessKey("AWS_ACCESS_KEY");
    auth_aws.setSecretKey("AWS_SECRET_KEY");
    // Don't forget to change the region to your particular region. (Also make the same change in the call to Connect below.)
    auth_aws.setRegion("us-west-2");
    auth_aws.setServiceName("dynamodb");
    // SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
    rest.setAuthAws(auth_aws) catch {};

    // URL: https://dynamodb.us-west-2.amazonaws.com/
    const b_tls = true;
    const port = 443;
    const b_auto_reconnect = true;
    rest.connect("dynamodb.us-west-2.amazonaws.com", port, b_tls, b_auto_reconnect) catch {
        std.debug.print("ConnectFailReason: {d}\n", .{rest.getConnectFailReason()});
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // Note: The above code does not need to be repeatedly called for each REST request.
    // The rest object can be setup once, and then many requests can be sent.  Chilkat will automatically
    // reconnect within a FullRequest* method as needed.  It is only the very first connection that is explicitly
    // made via the Connect method.

    // Use this online tool to generate code from sample JSON:
    // Generate Code to Create JSON

    // The following JSON is sent in the request body.

    // {
    //   "TableName": "Thread",
    //   "Key": {
    //     "ForumName": {
    //       "S": "Amazon DynamoDB"
    //     },
    //     "Subject": {
    //       "S": "How do I update multiple items?"
    //     }
    //   },
    //   "ConditionExpression": "attribute_not_exists(Replies)",
    //   "ReturnValues": "ALL_OLD"
    // }

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.updateString("TableName", "Thread") catch {};
    json.updateString("Key.ForumName.S", "Amazon DynamoDB") catch {};
    json.updateString("Key.Subject.S", "How do I update multiple items?") catch {};
    json.updateString("ConditionExpression", "attribute_not_exists(Replies)") catch {};
    json.updateString("ReturnValues", "ALL_OLD") catch {};

    rest.addHeader("Content-Type", "application/x-amz-json-1.0") catch {};
    rest.addHeader("X-Amz-Target", "DynamoDB_20120810.DeleteItem") catch {};
    rest.addHeader("Accept-Encoding", "identity") catch {};

    const sb_request_body = try chilkat.StringBuilder.init();
    defer sb_request_body.deinit();
    json.emitSb(sb_request_body) catch {};
    const sb_response_body = try chilkat.StringBuilder.init();
    defer sb_response_body.deinit();
    rest.fullRequestSb("POST", "/", sb_request_body, sb_response_body) catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    const resp_status_code = rest.getResponseStatusCode();
    std.debug.print("response status code = {d}\n", .{resp_status_code});
    if (resp_status_code >= 400) {
        std.debug.print("Response Status Code = {d}\n", .{resp_status_code});
        std.debug.print("Response Header:\n", .{});
        std.debug.print("{s}\n", .{try rest.getResponseHeader(alloc)});
        std.debug.print("Response Body:\n", .{});
        std.debug.print("{s}\n", .{try sb_response_body.getAsString(alloc)});
        return;
    }

    const json_response = try chilkat.JsonObject.init();
    defer json_response.deinit();
    json_response.loadSb(sb_response_body) catch {};

    json_response.setEmitCompact(false);
    std.debug.print("{s}\n", .{try json_response.emit(alloc)});

    // Sample JSON response:
    // (Sample code for parsing the JSON response is shown below)

    // {
    //   "Attributes": {
    //     "LastPostedBy": {
    //       "S": "fred@example.com"
    //     },
    //     "ForumName": {
    //       "S": "Amazon DynamoDB"
    //     },
    //     "LastPostDateTime": {
    //       "S": "201303201023"
    //     },
    //     "Tags": {
    //       "SS": [
    //         "Update",
    //         "Multiple Items",
    //         "HelpMe"
    //       ]
    //     },
    //     "Subject": {
    //       "S": "How do I update multiple items?"
    //     },
    //     "Message": {
    //       "S": "I want to update multiple items in a single call. What's the best way to do that?"
    //     }
    //   }
    // }

    // Sample code for parsing the JSON response...
    // Use the following online tool to generate parsing code from sample JSON:
    // Generate Parsing Code from JSON

    var str_val: [:0]const u8 = "";

    _ = try json_response.stringOf(alloc, "Attributes.LastPostedBy.S");
    _ = try json_response.stringOf(alloc, "Attributes.ForumName.S");
    _ = try json_response.stringOf(alloc, "Attributes.LastPostDateTime.S");
    _ = try json_response.stringOf(alloc, "Attributes.Subject.S");
    _ = try json_response.stringOf(alloc, "Attributes.Message.S");
    var i: i32 = 0;
    const count_i = json_response.sizeOfArray("Attributes.Tags.SS");
    while (i < count_i) {
        json_response.setI(i);
        str_val = try json_response.stringOf(alloc, "Attributes.Tags.SS[i]");
        i = i + 1;
    }
}