1 files changed, 179 insertions, 0 deletions
diff --git a/datastore-leveldb/src/web.cpp b/datastore-leveldb/src/web.cpp
new file mode 100644
index 0000000..443e782
--- /dev/null
+++ b/datastore-leveldb/src/web.cpp
@@ -0,0 +1,179 @@
+#include "web.h"
+#include "db.h"
+#include <algorithm>
+#include <chrono>
+#include <leveldb/comparator.h>
+
+static const leveldb::Comparator *cmp = leveldb::BytewiseComparator();
+
+static inline uint64_t now() {
+    return std::chrono::duration_cast<std::chrono::milliseconds>(
+        std::chrono::high_resolution_clock::now().time_since_epoch()).count();
+}
+
+// uint64_t is long
+inline void strToL(unsigned long int *l, std::string s) {
+	*l = std::stoul(s);
+}
+// uint64_t is long long
+inline void strToL(unsigned long long int *l, std::string s) {
+	*l = std::stoull(s);
+}
+
+static inline void reply_header(struct mg_connection *conn, const bool ok, const char *msg, const char *extra = "") {
+    mg_printf(conn,
+            "HTTP/1.1 %s %s\r\n"
+            "%s",
+            (ok) ? "200" : "500",
+            msg,
+            extra);
+}
+
+static inline bool parse_key(leveldb::Slice &&key, uint64_t *value) {
+    if (key.size() != 20+3) 
+        return false;
+    strToL(value, key.data()+3);
+    return true;
+}
+
+const boost::regex web_handle_api_value_R(
+    "/api/value/([a-zA-Z0-9\\.]+)");
+void web_handle_api_value(const boost::cmatch &match, struct mg_connection *conn) {
+    std::string sensor(match[1].str());
+    uint64_t timestamp = now();
+    char buf[1024];
+    int bytesRead = mg_read(conn, buf, 1024);
+    std::string value(buf, bytesRead);
+
+    if (db_insert(sensor, timestamp, value)) {
+        reply_header(conn, true, "OK Value received", "\r\n");
+    } else {
+        reply_header(conn, false, "Internal Error", "\r\n");
+    }
+}
+
+const boost::regex web_handle_api_value_timestamp_R(
+    "/api/value/([a-zA-Z0-9\\.]+)/([0-9]+)");
+void web_handle_api_value_timestamp(const boost::cmatch &match, struct mg_connection *conn) {
+    std::string sensor(match[1].str());
+    uint64_t timestamp; strToL(&timestamp, match[2].str());
+    char buf[1024];
+    int bytesRead = mg_read(conn, buf, 1024);
+    std::string value(buf, bytesRead);
+
+    if (db_insert(sensor, timestamp, value)) {
+        reply_header(conn, true, "OK Value received", "\r\n");
+    } else {
+        reply_header(conn, false, "Internal Error", "\r\n");
+    }
+}
+
+static inline void print_json_tuple(struct mg_connection *conn,
+        std::ostringstream &outbuf,
+        leveldb::Slice &&key,
+        leveldb::Slice &&value) {
+
+    size_t key_size =  key.size();
+    if (key_size != 20+3) {
+        std::cerr << "invalid key" << std::endl;
+        return;
+    }
+
+    unsigned int offset = 3; // "ts-"
+    // skip zeros in timestamp
+    while (offset < key_size-1 and *(key.data()+offset) == '0')
+        offset++;
+
+    outbuf << '[';
+    outbuf.write(key.data()+offset, key_size-offset);
+    outbuf << ',';
+    outbuf.write(value.data(), value.size());
+    outbuf << ']';
+
+    mg_write(conn, outbuf.str().c_str(), outbuf.tellp());
+}
+
+
+const boost::regex web_handle_api_range_R(
+    "/api/range/([a-zA-Z0-9\\.]+)/([0-9]+)/([0-9]+)");
+void web_handle_api_range(const boost::cmatch &match, struct mg_connection *conn) {
+    std::string sensor(match[1].str());
+    uint64_t start; strToL(&start, match[2].str());
+    uint64_t end; strToL(&end, match[3].str());
+    std::string key_start(std::move(db_make_key(start)));
+    std::string key_end(std::move(db_make_key(end)));
+
+    leveldb::DB *db = db_get(sensor);
+    if (db == nullptr) {
+        reply_header(conn, false, "Internal Error", "\r\n");
+        return;
+    }
+
+    reply_header(conn, true, "OK", "Content-Type: application/json\r\n\r\n");
+
+    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()) {
+        if (first) first = false;
+        else outbuf << ",";
+        print_json_tuple(conn, outbuf, it->key(), it->value());
+        outbuf.seekp(0);
+    }
+    mg_printf(conn, "]}\r\n");
+    delete it;
+}
+
+const boost::regex web_handle_api_range_size_R(
+    "/api/range/([a-zA-Z0-9\\.]+)/([0-9]+)/([0-9]+)/([0-9]+)");
+void web_handle_api_range_size(const boost::cmatch &match, struct mg_connection *conn) {
+    std::string sensor(match[1].str());
+    uint64_t start; strToL(&start, match[2].str());
+    uint64_t end; strToL(&end, match[3].str());
+    uint64_t size; strToL(&size, match[4].str());
+
+    leveldb::DB *db = db_get(sensor);
+    if (db == nullptr) {
+        reply_header(conn, false, "Internal Error", "\r\n");
+        return;
+    }
+
+    reply_header(conn, true, "OK", "Content-Type: application/json\r\n\r\n");
+
+    uint64_t step = std::max((uint64_t)1, (end-start) / size);
+
+    std::ostringstream out;
+    out << "{\"sensor\":\"" << sensor << "\", "
+        << "\"error\":null, "
+        << "\"size\":" << size << ", "
+        << "\"step\":" << step << ", "
+        << "\"data\":[";
+    mg_write(conn, out.str().c_str(), out.str().size());
+
+    bool first = true;
+    uint64_t actual_size = 0;
+    std::ostringstream outbuf;
+    leveldb::Iterator* it = db->NewIterator(leveldb::ReadOptions());
+    for (uint64_t key = start; key < end; key += step) {
+        it->Seek(db_make_key(key));
+        if (!it->Valid()) continue;
+
+        if (first) first = false;
+        else outbuf << ",";
+
+        print_json_tuple(conn, outbuf, it->key(), it->value());
+        outbuf.seekp(0);
+        actual_size++;
+    }
+    outbuf << "], \"actual_size\":" << actual_size << "}\r\n";
+    mg_write(conn, outbuf.str().c_str(), outbuf.tellp());
+    delete it;
+}