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extern "C" {
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include "mongoose.h"
}
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <map>
#include <forward_list>
#include <functional>
#include <mutex>
#include <boost/regex.hpp>
#include "leveldb/db.h"
#include "leveldb/comparator.h"
std::forward_list<std::pair<boost::regex,std::function<void(const boost::cmatch&, struct mg_connection *conn)>>> web_handler;
static std::map<std::string,leveldb::DB*> dbs;
struct mg_context *ctx;
bool sensor_name_is_sane(std::string& name) {
for (auto it = name.begin(); it != name.end(); ++it) {
if (not (*it >= '0' and *it <= '9' or
*it >= 'A' and *it <= 'Z' or
*it >= 'a' and *it <= 'z')) {
return false;
}
}
return true;
}
std::mutex getDBmutex;
leveldb::DB *getDB(std::string& name) {
getDBmutex.lock();
if (dbs.find(name) == dbs.end()) {
if (not sensor_name_is_sane(name)) {
getDBmutex.unlock();
return nullptr;
}
leveldb::DB *db;
leveldb::Options options;
options.create_if_missing = true;
leveldb::Status status = leveldb::DB::Open(options, "/tmp/testdb."+name, &db);
if (not status.ok()) {
std::cout << status.ToString() << std::endl;
getDBmutex.unlock();
return nullptr;
}
dbs[name] = db;
getDBmutex.unlock();
return db;
} else {
getDBmutex.unlock();
return dbs.at(name);
}
}
std::string make_key(uint64_t timestamp) {
std::stringstream key;
key << "ts-";
key << std::setfill('0') << std::setw(20) << timestamp;
return key.str();
}
void web_handle_api_value(const boost::cmatch &match, struct mg_connection *conn) {
const struct mg_request_info *request_info = mg_get_request_info(conn);
std::string sensor(match[1].str());
uint64_t timestamp = std::stoul(match[2].str());
char buf[1024];
int count = mg_read(conn, buf, 1024);
std::string value(buf, count);
leveldb::DB *db = getDB(sensor);
if (db == nullptr) {
std::cout << "failed to get db for " << sensor << std::endl;
mg_printf(conn, "HTTP/1.1 500 Internal Error\r\n\r\n");
return;
}
std::cout << "sensor=" << sensor << " key=" << make_key(timestamp) << std::endl;
db->Put(leveldb::WriteOptions(), make_key(timestamp), value);
mg_printf(conn, "HTTP/1.1 200 Value received\r\n\r\n");
}
void web_handle_api_range(const boost::cmatch &match, struct mg_connection *conn) {
static const leveldb::Comparator *cmp = leveldb::BytewiseComparator();
std::string sensor(match[1].str());
uint64_t start = std::stoul(match[2].str());
uint64_t end = std::stoul(match[3].str());
std::string key_start(std::move(make_key(start)));
std::string key_end(std::move(make_key(end)));
leveldb::DB *db = getDB(sensor);
if (db == nullptr) {
mg_printf(conn, "HTTP/1.1 500 Internal Error\r\n\r\n");
return;
}
mg_printf(conn,
"HTTP/1.1 200 Value received\r\n"
"Content-Type: application/json; encoding=UTF-8\r\n"
"\r\n");
std::cout << "sensor=" << sensor << " start=" << start << " end=" << end << std::endl;
std::ostringstream out;
out << "{'sensor':'" << sensor << "', 'error':null, 'data':[";
mg_write(conn, out.str().c_str(), out.str().size());
leveldb::Iterator* it = db->NewIterator(leveldb::ReadOptions());
bool first = true;
std::ostringstream outbuf;
for (it->Seek(key_start);
it->Valid() && cmp->Compare(it->key(), key_end) < 0;
it->Next()) {
const char *key = it->key().data();
size_t key_size = it->key().size();
if (key_size != 20+3) {
std::cerr << "invalid key" << std::endl;
return;
}
int offset = 3; //ts-
// skip zeros in timestamp
while (offset < key_size-1 and *(key+offset) == '0')
offset++;
if (first)
first = false;
else
outbuf << ',';
outbuf << '[';
outbuf.write(key+offset, key_size-offset);
outbuf << ',';
outbuf.write(it->value().data(), it->value().size());
outbuf << ']';
mg_write(conn, outbuf.str().c_str(), outbuf.tellp());
outbuf.seekp(0);
}
mg_printf(conn, "]}\r\n");
delete it;
}
int begin_request_handler(struct mg_connection *conn) {
boost::cmatch match;
const char *url = mg_get_request_info(conn)->uri;
for (auto item = web_handler.begin(); item != web_handler.end(); ++item) {
if (boost::regex_match(url, match, (*item).first)) {
(*item).second(match, conn);
return 1;
}
}
return 0;
}
struct sigaction old_action;
void sigint_handler(int s) {
// Stop the server.
mg_stop(ctx);
// Close databases
for (auto it = dbs.begin(); it != dbs.end(); ++it) {
std::cout << "Close " << (*it).first << std::endl;
delete (*it).second;
dbs.erase(it);
}
exit(0);
}
int main(int argc, char **argv) {
struct mg_callbacks callbacks;
const char *options[] = {
"listening_ports", "8080",
"document_root", "wwwroot",
NULL};
memset(&callbacks, 0, sizeof(callbacks));
callbacks.begin_request = begin_request_handler;
// Routing
web_handler.push_front(std::make_pair(
boost::regex("/api/value/([a-zA-Z0-9]+)/([0-9]+)"),
web_handle_api_value));
web_handler.push_front(std::make_pair(
boost::regex("/api/range/([a-zA-Z0-9]+)/([0-9]+)/([0-9]+)"),
web_handle_api_range));
// Signals: handle C-c
struct sigaction action;
memset(&action, 0, sizeof(action));
action.sa_handler = &sigint_handler;
sigaction(SIGINT, &action, &old_action);
// Start the web server.
ctx = mg_start(&callbacks, NULL, options);
pause();
return 1;
}
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