int main(int, char** )
{
Deferred<int> d;
Promise<int> p;
Resolver<int> r;
p = d.promise();
r = d.resolver();
p.done([] (int a) {
std::cout << "A = " << a << std::endl;
});
r.resolve(42);
return 0;
}
StrPair loadContent(const StrPair& url)
{
const int MAX_BUF_SIZE = 1024*1000;
const int READ_BUF_SIZE = 1024*16;
auto&& host = url.first;
auto&& path = url.second;
JLOG("loading url: " << host << ", " << path);
Resolver r;
Resolver::EndPoints ends = r.resolve(host, 80);
VERIFY(ends != Resolver::EndPoints(), "Cannot resolve hostname: " + host);
Socket s;
s.connect(*ends);
Str req =
"GET " + path + " HTTP/1.1" EOL
"Host: " + host + EOL EOL;
s.write(req);
Str resp;
Str buf;
size_t header = std::string::npos;
while (header == std::string::npos)
{
VERIFY(resp.size() < MAX_BUF_SIZE, "Header is too large");
buf.resize(READ_BUF_SIZE);
s.partialRead(buf);
VERIFY(!buf.empty(), "Empty buffer on partial read");
resp += buf;
header = resp.find(EOL EOL);
}
Str head = resp.substr(0, header);
header += 4; // add 2 EOLs
static const regex eStatus("^http/1\\.[01] ([\\d]{3})", regex::icase);
smatch whatStatus;
bool result = regex_search(head, whatStatus, eStatus);
VERIFY(result, "Invalid http status header");
Str status = whatStatus[1];
static const std::unordered_set<Str> allowedStatuses = {"200", "301", "302", "303"};
VERIFY(allowedStatuses.count(status), "Unexpected status: " + status);
static const regex e("content-length: *(\\d+)", regex::icase);
smatch what;
result = regex_search(head, what, e);
if (result)
{
int len = std::atoi(Str(what[1]).c_str());
VERIFY(len > 0 && len < MAX_BUF_SIZE, "Content length: invalid value");
buf.resize(len - (resp.size() - header));
s.read(buf);
resp += buf;
}
else
{
static const regex et("transfer-encoding: *chunked", regex::icase);
// read chunks
result = regex_search(head, et);
VERIFY(result, "Either content-length or transfer-encoding must be present in header");
while (resp.find(EOL EOL, resp.size() - 4) == std::string::npos)
{
VERIFY(resp.size() < MAX_BUF_SIZE, "Response is too large");
buf.resize(READ_BUF_SIZE);
s.partialRead(buf);
VERIFY(!buf.empty(), "Empty buffer on partial read");
resp += buf;
}
}
Str body = resp.substr(header);
return {host, body};
}
