git2cpp/src/wasm/stream.cpp at main · QuantStack/git2cpp · GitHub

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#ifdef EMSCRIPTEN

# include "stream.hpp"

# include <cstdlib>

# include <regex>

# include <sstream>

# include <string>

# include <emscripten.h>

# include "../utils/common.hpp"

# include "../utils/credentials.hpp"

# include "constants.hpp"

# include "read_buffer.hpp"

# include "response.hpp"

# include "utils.hpp"

// Buffer size used in transport_smart, hardcoded in libgit2.

# define EMFORGE_BUFSIZE 65536

// JavasScript functions.

EM_JS(const char*, js_base64_encode, (const char* input), {

const input_js = UTF8ToString(input);

const encoded = btoa(input_js);

return stringToNewUTF8(encoded);

});

EM_JS(void, js_delete_request, (int request_index), {

const cache = Module["git2cpp_js_cache"];

if (Object.hasOwn(cache, request_index))

{

delete cache[request_index];

}

});

// Return the latest error string set in JS. Caller must delete the returned const char*.

EM_JS(const char*, js_get_error, (void), {

const err = Module["git2cpp_js_error"];

if (!err)

{

return stringToNewUTF8("unknown error");

}

let msg = err.message;

if (err.name)

{

msg = err.name + ": " + msg;

}

return stringToNewUTF8(msg);

});

EM_JS(

int,

js_request,

(const char* url,

const char* method,

const char* content_type_header,

const char* authorization_header,

unsigned long request_timeout_ms,

size_t buffer_size),

{

const url_js = UTF8ToString(url);

const method_js = UTF8ToString(method);

const content_type_header_js = UTF8ToString(content_type_header);

const authorization_header_js = UTF8ToString(authorization_header);

try

{

const xhr = new XMLHttpRequest();

xhr.open(method_js, url_js, false);

xhr.responseType = "arraybuffer";

if (content_type_header_js.length > 0)

{

xhr.setRequestHeader("Content-Type", content_type_header_js);

}

if (authorization_header_js.length > 0)

{

// Should this only be set if using https? What about CORS via http?

xhr.setRequestHeader("Authorization", authorization_header_js);

}

if (!"{#{RUNTIME_TOKEN}#}".startsWith("{#{"))

{

xhr.setRequestHeader("x-runtime-token", "{#{RUNTIME_TOKEN}#}");

}

xhr.timeout = request_timeout_ms;

// Cache request info on JavaScript side so that it is available in subsequent calls

// without having to pass it back and forth to/from C++.

let request_index = 0;

if (!Module["git2cpp_js_cache"])

{

Module["git2cpp_js_cache"] = {"next_index": request_index};

}

else

{

request_index = Module["git2cpp_js_cache"]["next_index"]++;

}

Module["git2cpp_js_cache"][request_index] = {xhr, result_buffer_pointer: 0, buffer_size};

if (method_js == "GET")

{

xhr.send();

}

return request_index;

}

catch (err)

{

// clang-format off

// Store error for later retrieval

Module["git2cpp_js_error"] = { name: err.name ?? "", message : err.message ?? "" };

// clang-format on

(err.name == "TimeoutError" ? console.warn : console.error)(err);

return -1;

}

);

EM_JS(const char*, js_maybe_convert_url, (const char* url_str), {

// Convert URL to use CORS proxy based on env vars GIT_CORS_PROXY and possible

// GIT_CORS_PROXY_API_KEY.

// If no conversion occurs, return the original unconverted URL as a new string.

const url_js = UTF8ToString(url_str);

const url = new URL(url_js);

// clang-format off

const env = Module["ENV"] ?? {};

// clang-format on

const GIT_CORS_PROXY = env["GIT_CORS_PROXY"];

let ret = url_js; // Default to returning original unconverted URL as new string.

if (GIT_CORS_PROXY)

{

if (!GIT_CORS_PROXY.includes("{"))

{

ret = GIT_CORS_PROXY + url_js;

}

else

{

ret = GIT_CORS_PROXY;

ret = ret.replace("{url}", url_js);

ret = ret.replace("{url:encode}", encodeURIComponent(url_js));

ret = ret.replace("{protocol}", url.protocol);

ret = ret.replace("{protocol:encode}", encodeURIComponent(url.protocol));

ret = ret.replace("{host}", url.host);

ret = ret.replace("{host:encode}", encodeURIComponent(url.host));

ret = ret.replace("{path}", url.pathname + url.search);

ret = ret.replace("{path:encode}", encodeURIComponent(url.pathname + url.search));

const api_key = env["GIT_CORS_PROXY_API_KEY"];

if (api_key)

{

ret = ret.replace("{api_key}", api_key);

}

// Ignore any other use of curly braces.

}

return stringToNewUTF8(ret);

});

EM_JS(

size_t,

js_read,

(int request_index,

char* buffer,

size_t buffer_size,

bool first_read, // Set subsequent arguments only if this is true.

int32_t* status,

const char** status_text,

int64_t* total_bytes,

const char** response_headers),

{

try

{

const cache = Module["git2cpp_js_cache"];

const request = cache[request_index];

const {xhr} = request;

if (request.content)

{

xhr.send(request.content.buffer);

request.content = null;

}

let byte_length = 0; // Total number of bytes that will be returned.

let bytes_read = 0; // Number of bytes returned by this call.

if (xhr.response && xhr.response.byteLength)

{

byte_length = xhr.response.byteLength;

bytes_read = byte_length - request.result_buffer_pointer;

if (bytes_read > buffer_size)

{

bytes_read = buffer_size;

}

if (first_read)

{

// clang-format off

// Caller must delete the returned status_text and response_headers.

setValue(status, xhr.status, 'i32*');

setValue(status_text, stringToNewUTF8(xhr.statusText ?? ""), 'i8**');

setValue(total_bytes, byte_length, 'i64*');

setValue(response_headers, stringToNewUTF8(xhr.getAllResponseHeaders() ?? ""), 'i8**');

// clang-format on

}

if (bytes_read > 0)

{

const responseChunk = new Uint8Array(xhr.response, request.result_buffer_pointer, bytes_read);

writeArrayToMemory(responseChunk, buffer);

request.result_buffer_pointer += bytes_read;

}

return bytes_read

}

catch (err)

{

// clang-format off

// Store error for later retrieval

Module["git2cpp_js_error"] = { name: err.name ?? "", message : err.message ?? "" };

// clang-format on

(err.name == "TimeoutError" ? console.warn : console.error)(err);

return -1;

}

);

EM_JS(void, js_warning, (const char* msg), {

const msg_js = UTF8ToString(msg);

console.warning(msg_js);

});

EM_JS(int, js_write, (int request_index, const char* buffer, size_t buffer_size), {

try

{

const cache = Module["git2cpp_js_cache"];

const request = cache[request_index];

// Note the slice(0) is important.

const buffer_js = new Uint8Array(HEAPU8.buffer, buffer, buffer_size).slice(0);

if (!request.content)

{

request.content = buffer_js;

}

else

{

const content = new Uint8Array(request.content.length + buffer_js.length);

content.set(request.content);

content.set(buffer_js, request.content.length);

request.content = content;

}

return 0;

}

catch (err)

{

// Store error for later retrieval

// clang-format off

Module["git2cpp_js_error"] = { name: err.name ?? "", message : err.message ?? "" };

// clang-format on

(err.name == "TimeoutError" ? console.warn : console.error)(err);

return -1;

}

});

// C wrapper functions that call JavaScript functions.

static std::string base64_encode(std::string_view str)

{

// Use browser's base64 encoding.

const char* encoded = js_base64_encode(str.data());

std::string ret(encoded);

delete encoded; // Delete const char* allocated in JavaScript.

return ret;

}

static void convert_js_to_git_error(wasm_http_stream* stream)

{

// Convert error on JS side to git error.

const char* error_str = js_get_error();

if (std::string_view(error_str).starts_with("NetworkError:"))

{

git_error_set(

GIT_ERROR_HTTP,

"network error sending request to %s, see the browser console and/or network tab for more details",

stream->m_unconverted_url.c_str()

);

}

else if (std::string_view(error_str).starts_with("TimeoutError:"))

{

auto env_var = std::getenv(WASM_HTTP_TRANSPORT_TIMEOUT_NAME.data());

std::string value = env_var != nullptr ? env_var

: std::to_string(WASM_HTTP_TRANSPORT_TIMEOUT_DEFAULT_S);

git_error_set(

GIT_ERROR_HTTP,

"network request timed out connecting to %s. You can set a longer timeout in seconds using the environment variable %s, the %s value is %s seconds.",

stream->m_unconverted_url.c_str(),

WASM_HTTP_TRANSPORT_TIMEOUT_NAME.data(),

env_var != nullptr ? "current" : "default",

value.c_str()

);

}

else

{

git_error_set(GIT_ERROR_HTTP, "%s", error_str);

}

delete error_str; // Delete const char* allocated in JavaScript.

}

static int create_request(wasm_http_stream* stream, std::string_view content_header)

{

stream->m_request_index = js_request(

stream->get_full_url().c_str(),

name_for_method(stream->m_service.m_method).c_str(),

content_header.data(),

stream->m_subtransport->m_authorization_header.c_str(),

stream->m_subtransport->m_request_timeout_ms,

EMFORGE_BUFSIZE

);

return stream->m_request_index;

}

static void delete_request(wasm_http_stream* stream)

{

if (stream->m_request_index != -1)

{

js_delete_request(stream->m_request_index);

stream->m_request_index = -1;

}

static int read(wasm_http_stream* stream, read_buffer_t& read_buffer, bool is_read_response)

{

if (is_read_response)

{

// Response from a write.

if (stream->m_request_index == -1)

{

git_error_set(

GIT_ERROR_HTTP,

"read_response called without pending request to %s",

stream->m_unconverted_url.c_str()

);

return -1;

}

else

{

if (stream->m_request_index == -1)

{

// Send http(s) request if have not already done so.

if (create_request(stream, stream->m_service.m_response_type.c_str()) < 0)

{

convert_js_to_git_error(stream);

return -1;

}

auto& response = stream->m_response;

bool first_read = response.m_read_count == 0;

const char* status_text = nullptr;

const char* response_headers = nullptr;

// Actual read.

size_t bytes_read = js_read(

stream->m_request_index,

read_buffer.m_buffer,

read_buffer.m_buffer_size,

first_read,

&response.m_status,

&status_text,

&response.m_total_bytes,

&response_headers

);

stream->m_response.m_read_count++;

if (bytes_read == static_cast<size_t>(-1))

{

convert_js_to_git_error(stream);

// Delete const char* allocated in JavaScript.

delete status_text;

delete response_headers;

return -1;

}

if (first_read)

{

response.m_status_text = status_text;

delete status_text; // Delete const char* allocated in JavaScript.

// Split single string with response headers separated by \r\n into individual headers.

auto lines = split_input_at_newlines(response_headers);

for (const auto& line : lines)

{

auto pos = line.find(":");

if (pos == std::string::npos)

{

// Skip invalid lines. Should this be an error condition?

continue;

}

response.add_header(line.substr(0, pos), line.substr(pos + 1));

}

delete response_headers; // Delete const char* allocated in JavaScript.

// If successful, check expected response content-type is correct.

if (response.m_status == GIT_HTTP_STATUS_OK)

{

auto expected_response_type = stream->m_service.m_response_type;

if (!expected_response_type.empty()

&& !response.has_header_matches("content-type", expected_response_type))

{

// Not sure this should be checked at all, as CORS proxy may be doing something

// with it.

git_error_set(

GIT_ERROR_HTTP,

"expected response content-type header '%s' to request %s",

expected_response_type.c_str(),

stream->m_unconverted_url.c_str()

);

return -1;

}

if (!maybe_prompt_to_download(response.m_total_bytes))

{

git_error_set(GIT_ERROR_NONE, "Download aborted");

return -1;

}

*read_buffer.m_bytes_read = bytes_read;

return 0;

}

static int write(wasm_http_stream* stream, const char* buffer, size_t buffer_size)

{

if (stream->m_request_index == -1)

{

// If there is not already a request opened, do so now.

if (create_request(stream, stream->m_service.m_request_type.c_str()) < 0)

{

convert_js_to_git_error(stream);

return -1;

}

int error = js_write(stream->m_request_index, buffer, buffer_size);

if (error < 0)

{

convert_js_to_git_error(stream);

return -1;

}

return 0;

}

// C credential functions.

static int create_credential(wasm_http_stream* stream)

{

wasm_http_subtransport* subtransport = stream->m_subtransport;

// Delete old credential and authorization header.

if (subtransport->m_credential != nullptr)

{

subtransport->m_credential->free(subtransport->m_credential);

subtransport->m_credential = nullptr;

}

subtransport->m_authorization_header = "";

if (!want_user_credentials())

{

// Check that response headers show support for 'www-authenticate: Basic'.

if (!stream->m_response.has_header_starts_with("www-authenticate", "Basic"))

{

git_error_set(

GIT_ERROR_HTTP,

"remote host for request %s does not support Basic authentication",

stream->m_unconverted_url.c_str()

);

return -1;

}

// Get credentials from user via libgit2 registered callback.

int err;

if ((err = git_transport_smart_credentials(

&subtransport->m_credential,

subtransport->m_owner,

nullptr,

GIT_CREDENTIAL_USERPASS_PLAINTEXT

))

< 0)

{

if (err == GIT_PASSTHROUGH)

{

// Use same error message as libgit2

git_error_set(GIT_ERROR_HTTP, "remote authentication required but no callback set");

}

// credentials_callback will have set git error.

return err;

}

if (subtransport->m_credential->credtype != GIT_CREDENTIAL_USERPASS_PLAINTEXT)

{

git_error_set(GIT_ERROR_HTTP, "Unexpected credential type");

return -1;

}

// Create authorization header from username and password.

// Cast is OK as checked above that credential is a GIT_CREDENTIAL_USERPASS_PLAINTEXT.

auto userpass = reinterpret_cast<git_credential_userpass_plaintext*>(subtransport->m_credential);

std::ostringstream buffer;

buffer << userpass->username << ':' << userpass->password;

subtransport->m_authorization_header = "Basic " + base64_encode(buffer.str());

return 0;

}

// C wasm_http_stream functions.

wasm_http_stream::wasm_http_stream(wasm_http_subtransport* subtransport, http_service service)

: m_subtransport(subtransport)

, m_service(service)

, m_request_index(-1)

{

}

bool wasm_http_stream::ensure_final_url(const std::string final_url)

{

// Must be using a CORS proxy that has redirected, so store updated base URL to reuse.

if (final_url.ends_with(m_service.m_url))

{

// Remove service URL from end of final URL to give new base URL.

auto base_url = final_url.substr(0, final_url.size() - m_service.m_url.size());

if (m_subtransport->m_base_url != base_url)

{

m_subtransport->m_base_url = base_url;

return true;

}

else

{

std::string msg = "Unexpected x-final-url: " + final_url;

js_warning(msg.c_str());

}

return false;

}

bool wasm_http_stream::ensure_https()

{

const std::string http = "http:";

if (m_subtransport->m_base_url.starts_with(http))

{

m_subtransport->m_base_url.replace(0, http.size(), "https:");

return true;

}

return false;

}

std::string wasm_http_stream::get_full_url()

{

// Base URL never ends with a slash, service URL always begins with a slash.

m_unconverted_url = m_subtransport->m_base_url + m_service.m_url;

const char* converted_url = js_maybe_convert_url(m_unconverted_url.c_str());

std::string ret = converted_url;

delete converted_url; // Delete const char* allocated in JavaScript.

return ret;

}

void wasm_http_stream_free(git_smart_subtransport_stream* s)

{

wasm_http_stream* stream = reinterpret_cast<wasm_http_stream*>(s);

delete_request(stream);

delete stream;

}

int wasm_http_stream_read(git_smart_subtransport_stream* s, char* buffer, size_t buffer_size, size_t* bytes_read)

{

wasm_http_stream* stream = reinterpret_cast<wasm_http_stream*>(s);

read_buffer_t read_buffer(buffer, buffer_size, bytes_read);

bool send = true;

while (send)

{

if (read(stream, read_buffer, false) == static_cast<size_t>(-1))

{

return -1; // git error already set.

}

send = false;

auto final_url_header = stream->m_response.get_header("x-final-url");

if (final_url_header.has_value() && stream->ensure_final_url(final_url_header.value())

&& stream->m_response.m_status != GIT_HTTP_STATUS_OK)

{

// Resend only if status not OK, if OK next request will use updated URL.

send = true;

}

if (stream->m_response.has_header("strict-transport-security") && stream->ensure_https()

&& stream->m_response.m_status != GIT_HTTP_STATUS_OK)

{

// Resend only if status not OK, if OK next request will use https not http.

send = true;

}

if (stream->m_response.m_status == GIT_HTTP_STATUS_UNAUTHORIZED)

{

// Request and create new credentials.

if (create_credential(stream) < 0)

{

return -1; // git error already set.

}

send = true; // Resend will use updated credentials.

}

if (send)

{

delete_request(stream);

stream->m_response.clear();

}

if (stream->m_response.m_status != GIT_HTTP_STATUS_OK)

{

stream->m_response.set_git_error(stream->m_unconverted_url);

return -1;

}

return 0;

}

int wasm_http_stream_read_response(git_smart_subtransport_stream* s, char* buffer, size_t buffer_size, size_t* bytes_read)

{

wasm_http_stream* stream = reinterpret_cast<wasm_http_stream*>(s);

read_buffer_t read_buffer(buffer, buffer_size, bytes_read);

int error = read(stream, read_buffer, true);

// May need similar handling of response status and headers as occurs in read() above, but so

// far this has not been necessary.

if (error == 0 && stream->m_response.m_status != GIT_HTTP_STATUS_OK)

{

stream->m_response.set_git_error(stream->m_unconverted_url);

error = -1;

}

return error;

}

int wasm_http_stream_write(git_smart_subtransport_stream* s, const char* buffer, size_t buffer_size)

{

wasm_http_stream* stream = reinterpret_cast<wasm_http_stream*>(s);

return write(stream, buffer, buffer_size);

}

#endif // EMSCRIPTEN

git2cpp/src/wasm/stream.cpp at main · QuantStack/git2cpp · GitHub

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