aws-sdk-for-zig/src/aws_http.zig
Emil Lerch ab1060b145
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2022-05-31 18:47:59 -07:00

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Zig

//! This module provides a low level http interface for working with AWS
//! It also provides an option to operate outside the AWS ecosystem through
//! the makeRequest call with a null signingOptions.
//!
//! Typical usage:
//! const client = awshttp.AwsHttp.init(allocator);
//! defer client.deinit()
//! const result = client.callApi (or client.makeRequest)
//! defer result.deinit();
const std = @import("std");
const base = @import("aws_http_base.zig");
const signing = @import("aws_signing.zig");
const credentials = @import("aws_credentials.zig");
const zfetch = @import("zfetch");
const tls = @import("iguanaTLS");
const CN_NORTH_1_HASH = std.hash_map.hashString("cn-north-1");
const CN_NORTHWEST_1_HASH = std.hash_map.hashString("cn-northwest-1");
const US_ISO_EAST_1_HASH = std.hash_map.hashString("us-iso-east-1");
const US_ISOB_EAST_1_HASH = std.hash_map.hashString("us-isob-east-1");
const log = std.log.scoped(.awshttp);
const amazon_root_ca_1 = @embedFile("../Amazon_Root_CA_1.pem");
pub const default_root_ca = amazon_root_ca_1;
pub const AwsError = error{
AddHeaderError,
AlpnError,
CredentialsError,
HttpClientConnectError,
HttpRequestError,
SignableError,
SigningInitiationError,
TlsError,
RequestCreateError,
SetupConnectionError,
StatusCodeError,
SetRequestMethodError,
SetRequestPathError,
};
pub const Options = struct {
region: []const u8 = "aws-global",
dualstack: bool = false,
sigv4_service_name: ?[]const u8 = null,
};
pub const Header = base.Header;
pub const HttpRequest = base.Request;
pub const HttpResult = base.Result;
const EndPoint = struct {
uri: []const u8,
host: []const u8,
scheme: []const u8,
port: u16,
path: []const u8,
allocator: std.mem.Allocator,
fn deinit(self: EndPoint) void {
self.allocator.free(self.uri);
self.allocator.free(self.host);
self.allocator.free(self.path);
}
};
pub const AwsHttp = struct {
allocator: std.mem.Allocator,
trust_chain: ?tls.x509.CertificateChain,
const Self = @This();
/// Recommend usage is init(allocator, awshttp.default_root_ca)
/// Passing null for root_pem will result in no TLS verification
pub fn init(allocator: std.mem.Allocator, root_pem: ?[]const u8) !Self {
var trust_chain: ?tls.x509.CertificateChain = null;
if (root_pem) |p| {
var fbs = std.io.fixedBufferStream(p);
trust_chain = try tls.x509.CertificateChain.from_pem(allocator, fbs.reader());
}
return Self{
.allocator = allocator,
.trust_chain = trust_chain,
// .credentialsProvider = // creds provider could be useful
};
}
pub fn deinit(self: *AwsHttp) void {
if (self.trust_chain) |c| c.deinit();
_ = self;
log.debug("Deinit complete", .{});
}
/// callApi allows the calling of AWS APIs through a higher-level interface.
/// It will calculate the appropriate endpoint and action parameters for the
/// service called, and will set up the signing options. The return
/// value is simply a raw HttpResult
pub fn callApi(self: Self, service: []const u8, request: HttpRequest, options: Options) !HttpResult {
// This function or regionSubDomain needs altering for virtual host
// addressing (for S3). Botocore, and I suspect other SDKs, have
// hardcoded exceptions for S3:
// https://github.com/boto/botocore/blob/f2b0dbb800b8dc2a3541334d5ca1190faf900150/botocore/utils.py#L2160-L2181
// Boto assumes virtual host addressing unless the endpoint url is configured
//
// NOTE: There are 4 rest_xml services. They are:
// * CloudFront
// * Route53
// * S3
// * S3 control
//
// All 4 are non-standard. Route53 and CloudFront are global endpoints
// S3 uses virtual host addressing (except when it doesn't), and
// S3 control uses <account-id>.s3-control.<region>.amazonaws.com
//
// So this regionSubDomain call needs to handle generic customization
const endpoint = try endpointForRequest(self.allocator, service, request, options);
defer endpoint.deinit();
log.debug("Calling endpoint {s}", .{endpoint.uri});
// TODO: Should we allow customization here?
const creds = try credentials.getCredentials(self.allocator, .{});
defer creds.deinit();
const signing_config: signing.Config = .{
.region = getRegion(service, options.region),
.service = options.sigv4_service_name orelse service,
.credentials = creds,
};
return try self.makeRequest(endpoint, request, signing_config);
}
/// makeRequest is a low level http/https function that can be used inside
/// or outside the context of AWS services. To use it outside AWS, simply
/// pass a null value in for signing_options.
///
/// Otherwise, it will simply take a URL endpoint (without path information),
/// HTTP method (e.g. GET, POST, etc.), and request body.
///
/// At the moment this does not allow changing headers, but addtional
/// ones are possible. This is likely to change. Current headers are:
///
/// Accept: application/json
/// User-Agent: zig-aws 1.0, Powered by the AWS Common Runtime.
/// Content-Type: application/x-www-form-urlencoded
/// Content-Length: (length of body)
///
/// Return value is an HttpResult, which will need the caller to deinit().
pub fn makeRequest(self: Self, endpoint: EndPoint, request: HttpRequest, signing_config: ?signing.Config) !HttpResult {
var request_cp = request;
log.debug("Request Path: {s}", .{request_cp.path});
log.debug("Endpoint Path (actually used): {s}", .{endpoint.path});
log.debug("Query: {s}", .{request_cp.query});
log.debug("Request additional header count: {d}", .{request_cp.headers.len});
log.debug("Method: {s}", .{request_cp.method});
log.debug("body length: {d}", .{request_cp.body.len});
log.debug("Body\n====\n{s}\n====", .{request_cp.body});
// Endpoint calculation might be different from the request (e.g. S3 requests)
// We will use endpoint instead
request_cp.path = endpoint.path;
var request_headers = std.ArrayList(base.Header).init(self.allocator);
defer request_headers.deinit();
const len = try addHeaders(self.allocator, &request_headers, endpoint.host, request_cp.body, request_cp.content_type, request_cp.headers);
defer if (len) |l| self.allocator.free(l);
request_cp.headers = request_headers.items;
if (signing_config) |opts| request_cp = try signing.signRequest(self.allocator, request_cp, opts);
defer {
if (signing_config) |opts| {
signing.freeSignedRequest(self.allocator, &request_cp, opts);
}
}
try zfetch.init(); // This only does anything on Windows. Not sure how performant it is to do this on every request
defer zfetch.deinit();
var headers = zfetch.Headers.init(self.allocator);
defer headers.deinit();
for (request_cp.headers) |header|
try headers.appendValue(header.name, header.value);
log.debug("All Request Headers (zfetch):", .{});
for (headers.list.items) |h| {
log.debug("\t{s}: {s}", .{ h.name, h.value });
}
const url = try std.fmt.allocPrint(self.allocator, "{s}{s}{s}", .{ endpoint.uri, request_cp.path, request_cp.query });
defer self.allocator.free(url);
log.debug("Request url: {s}", .{url});
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// PLEASE READ!! IF YOU ARE LOOKING AT THIS LINE OF CODE DUE TO A
// SEGFAULT IN INIT, IT IS PROBABLY BECAUSE THE HOST DOES NOT EXIST
// https://github.com/ziglang/zig/issues/11358
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
var req = try zfetch.Request.init(self.allocator, url, self.trust_chain);
defer req.deinit();
const method = std.meta.stringToEnum(zfetch.Method, request_cp.method).?;
try req.do(method, headers, if (request_cp.body.len == 0) null else request_cp.body);
// TODO: Timeout - is this now above us?
log.debug("Request Complete. Response code {d}: {s}", .{ req.status.code, req.status.reason });
log.debug("Response headers:", .{});
var resp_headers = try std.ArrayList(Header).initCapacity(self.allocator, req.headers.list.items.len);
defer resp_headers.deinit();
var content_length: usize = 0;
for (req.headers.list.items) |h| {
log.debug(" {s}: {s}", .{ h.name, h.value });
resp_headers.appendAssumeCapacity(.{
.name = try (self.allocator.dupe(u8, h.name)),
.value = try (self.allocator.dupe(u8, h.value)),
});
if (content_length == 0 and std.ascii.eqlIgnoreCase("content-length", h.name))
content_length = std.fmt.parseInt(usize, h.value, 10) catch 0;
}
const reader = req.reader();
var buf: [65535]u8 = undefined;
var resp_payload = try std.ArrayList(u8).initCapacity(self.allocator, content_length);
defer resp_payload.deinit();
while (true) {
const read = try reader.read(&buf);
try resp_payload.appendSlice(buf[0..read]);
if (read == 0) break;
}
log.debug("raw response body:\n{s}", .{resp_payload.items});
const rc = HttpResult{
.response_code = req.status.code,
.body = resp_payload.toOwnedSlice(),
.headers = resp_headers.toOwnedSlice(),
.allocator = self.allocator,
};
return rc;
}
};
fn getRegion(service: []const u8, region: []const u8) []const u8 {
if (std.mem.eql(u8, service, "cloudfront")) return "us-east-1";
return region;
}
fn addHeaders(allocator: std.mem.Allocator, headers: *std.ArrayList(base.Header), host: []const u8, body: []const u8, content_type: []const u8, additional_headers: []Header) !?[]const u8 {
var has_content_type = false;
for (additional_headers) |h| {
if (std.ascii.eqlIgnoreCase(h.name, "Content-Type")) {
has_content_type = true;
break;
}
}
try headers.append(.{ .name = "Accept", .value = "application/json" });
try headers.append(.{ .name = "Host", .value = host });
try headers.append(.{ .name = "User-Agent", .value = "zig-aws 1.0, Powered by the AWS Common Runtime." });
if (!has_content_type)
try headers.append(.{ .name = "Content-Type", .value = content_type });
try headers.appendSlice(additional_headers);
if (body.len > 0) {
const len = try std.fmt.allocPrint(allocator, "{d}", .{body.len});
try headers.append(.{ .name = "Content-Length", .value = len });
return len;
}
return null;
}
fn getEnvironmentVariable(allocator: std.mem.Allocator, key: []const u8) !?[]const u8 {
return std.process.getEnvVarOwned(allocator, key) catch |e| switch (e) {
std.process.GetEnvVarOwnedError.EnvironmentVariableNotFound => return null,
else => return e,
};
}
fn endpointForRequest(allocator: std.mem.Allocator, service: []const u8, request: HttpRequest, options: Options) !EndPoint {
const environment_override = try getEnvironmentVariable(allocator, "AWS_ENDPOINT_URL");
if (environment_override) |override| {
const uri = try allocator.dupeZ(u8, override);
return endPointFromUri(allocator, uri);
}
// Fallback to us-east-1 if global endpoint does not exist.
const realregion = if (std.mem.eql(u8, options.region, "aws-global")) "us-east-1" else options.region;
const dualstack = if (options.dualstack) ".dualstack" else "";
const domain = switch (std.hash_map.hashString(options.region)) {
US_ISO_EAST_1_HASH => "c2s.ic.gov",
CN_NORTH_1_HASH, CN_NORTHWEST_1_HASH => "amazonaws.com.cn",
US_ISOB_EAST_1_HASH => "sc2s.sgov.gov",
else => "amazonaws.com",
};
if (try endpointException(allocator, service, request, options, realregion, dualstack, domain)) |e|
return e;
const uri = try std.fmt.allocPrintZ(allocator, "https://{s}{s}.{s}.{s}", .{ service, dualstack, realregion, domain });
const host = try allocator.dupe(u8, uri["https://".len..]);
log.debug("host: {s}, scheme: {s}, port: {}", .{ host, "https", 443 });
return EndPoint{
.uri = uri,
.host = host,
.scheme = "https",
.port = 443,
.allocator = allocator,
.path = try allocator.dupe(u8, request.path),
};
}
fn endpointException(
allocator: std.mem.Allocator,
service: []const u8,
request: HttpRequest,
options: Options,
realregion: []const u8,
dualstack: []const u8,
domain: []const u8,
) !?EndPoint {
if (std.mem.eql(u8, service, "cloudfront")) {
return EndPoint{
.uri = try allocator.dupe(u8, "https://cloudfront.amazonaws.com"),
.host = try allocator.dupe(u8, "cloudfront.amazonaws.com"),
.scheme = "https",
.port = 443,
.allocator = allocator,
.path = try allocator.dupe(u8, request.path),
};
}
if (std.mem.eql(u8, service, "s3")) {
if (request.path.len == 1 or std.mem.indexOf(u8, request.path[1..], "/") == null)
return null;
// We need to adjust the host and the path to accomodate virtual
// host addressing. This only applies to bucket operations, but
// right now I'm hoping that bucket operations do not include a path
// component, so will be handled by the return null statement above.
const bucket_name = s3BucketFromPath(request.path);
const rest_of_path = request.path[bucket_name.len + 1 ..];
// TODO: Implement
_ = options;
const uri = try std.fmt.allocPrintZ(allocator, "https://{s}.{s}{s}.{s}.{s}", .{ bucket_name, service, dualstack, realregion, domain });
const host = try allocator.dupe(u8, uri["https://".len..]);
log.debug("S3 host: {s}, scheme: {s}, port: {}", .{ host, "https", 443 });
return EndPoint{
.uri = uri,
.host = host,
.scheme = "https",
.port = 443,
.allocator = allocator,
.path = try allocator.dupe(u8, rest_of_path),
};
}
return null;
}
fn s3BucketFromPath(path: []const u8) []const u8 {
var in_bucket = false;
var start: usize = 0;
for (path) |c, inx| {
if (c == '/') {
if (in_bucket) return path[start..inx];
start = inx + 1;
in_bucket = true;
}
}
unreachable;
}
/// creates an endpoint from a uri string.
///
/// allocator: Will be used only to construct the EndPoint struct
/// uri: string constructed in such a way that deallocation is needed
fn endPointFromUri(allocator: std.mem.Allocator, uri: []const u8) !EndPoint {
var scheme: []const u8 = "";
var host: []const u8 = "";
var port: u16 = 443;
var host_start: usize = 0;
var host_end: usize = 0;
for (uri) |ch, i| {
switch (ch) {
':' => {
if (!std.mem.eql(u8, scheme, "")) {
// here to end is port - this is likely a bug if ipv6 address used
const rest_of_uri = uri[i + 1 ..];
port = try std.fmt.parseUnsigned(u16, rest_of_uri, 10);
host_end = i;
}
},
'/' => {
if (host_start == 0) {
host_start = i + 2;
scheme = uri[0 .. i - 1];
if (std.mem.eql(u8, scheme, "http")) {
port = 80;
} else {
port = 443;
}
}
},
else => continue,
}
}
if (host_end == 0) {
host_end = uri.len;
}
host = try allocator.dupe(u8, uri[host_start..host_end]);
log.debug("host: {s}, scheme: {s}, port: {}", .{ host, scheme, port });
return EndPoint{
.uri = uri,
.host = host,
.scheme = scheme,
.allocator = allocator,
.port = port,
.path = try allocator.dupe(u8, "/"),
};
}
test "endpointForRequest standard operation" {
const request: HttpRequest = .{};
const options: Options = .{
.region = "us-west-2",
.dualstack = false,
.sigv4_service_name = null,
};
const allocator = std.testing.allocator;
const service = "dynamodb";
const endpoint = try endpointForRequest(allocator, service, request, options);
defer endpoint.deinit();
try std.testing.expectEqualStrings("https://dynamodb.us-west-2.amazonaws.com", endpoint.uri);
}
test "endpointForRequest for cloudfront" {
const request = HttpRequest{};
const options = Options{
.region = "us-west-2",
.dualstack = false,
.sigv4_service_name = null,
};
const allocator = std.testing.allocator;
const service = "cloudfront";
const endpoint = try endpointForRequest(allocator, service, request, options);
defer endpoint.deinit();
try std.testing.expectEqualStrings("https://cloudfront.amazonaws.com", endpoint.uri);
}
test "endpointForRequest for s3" {
const request = HttpRequest{};
const options = Options{
.region = "us-east-2",
.dualstack = false,
.sigv4_service_name = null,
};
const allocator = std.testing.allocator;
const service = "s3";
const endpoint = try endpointForRequest(allocator, service, request, options);
defer endpoint.deinit();
try std.testing.expectEqualStrings("https://s3.us-east-2.amazonaws.com", endpoint.uri);
}
test "endpointForRequest for s3 - specific bucket" {
const request = HttpRequest{
.path = "/bucket/key",
};
const options = Options{
.region = "us-east-2",
.dualstack = false,
.sigv4_service_name = null,
};
const allocator = std.testing.allocator;
const service = "s3";
const endpoint = try endpointForRequest(allocator, service, request, options);
defer endpoint.deinit();
try std.testing.expectEqualStrings("https://bucket.s3.us-east-2.amazonaws.com", endpoint.uri);
try std.testing.expectEqualStrings("/key", endpoint.path);
}