MXS-2208 Add simple Http library

- Built on top of Curl
- Currently only GET

maxutils/maxbase/src/http.cc

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2018 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2022-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxbase/http.hh>
+#include <algorithm>
+#include <curl/curl.h>
+#include <maxbase/assert.h>
+
+using std::map;
+using std::string;
+
+namespace
+{
+
+// TODO: Remove once trim is in maxbase.
+// trim from beginning (in place)
+inline void ltrim(std::string &s) {
+    s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](int ch) {
+        return !std::isspace(ch);
+    }));
+}
+
+// trim from end (in place)
+inline void rtrim(std::string &s) {
+    s.erase(std::find_if(s.rbegin(), s.rend(), [](int ch) {
+        return !std::isspace(ch);
+    }).base(), s.end());
+}
+
+// trim from both ends (in place)
+inline void trim(std::string &s) {
+    ltrim(s);
+    rtrim(s);
+}
+
+template<class T>
+inline void checked_curl_setopt(CURL* pCurl, CURLoption option, T value)
+{
+    MXB_AT_DEBUG(CURLcode rv =) curl_easy_setopt(pCurl, option, value);
+    mxb_assert(rv == CURLE_OK);
+}
+
+// https://curl.haxx.se/libcurl/c/CURLOPT_WRITEFUNCTION.html
+size_t write_callback(char* ptr, size_t size, size_t nmemb, void* userdata)
+{
+    // ptr points to the delivered data, and the size of that data is nmemb;
+    // size is always 1.
+    mxb_assert(size == 1);
+
+    string* pString = static_cast<string*>(userdata);
+
+    if (nmemb > 0)
+    {
+        pString->append(ptr, nmemb);
+    }
+
+    return nmemb;
+}
+
+// https://curl.haxx.se/libcurl/c/CURLOPT_HEADERFUNCTION
+size_t header_callback(char* ptr, size_t size, size_t nmemb, void* userdata)
+{
+    size_t len = size * nmemb;
+
+    if (len > 0)
+    {
+        map<string, string>* pHeaders = static_cast<std::map<string, string>*>(userdata);
+
+        char* end = ptr + len;
+        char* i = std::find(ptr, end, ':');
+
+        if (i != end)
+        {
+            string key(ptr, i - ptr);
+            ++i;
+            string value(i, end - i);
+            trim(key);
+            trim(value);
+            pHeaders->insert(std::make_pair(key, value));
+        }
+    }
+
+    return len;
+}
+
+}
+
+
+namespace maxbase
+{
+
+namespace http
+{
+
+Result get(const std::string& url, const Config& config)
+{
+    return std::move(get(url, "", "", config));
+}
+
+Result get(const std::string& url, const std::string& user, const std::string& password, const Config& config)
+{
+    Result res;
+    char errbuf[CURL_ERROR_SIZE + 1] = "";
+    CURL* pCurl = curl_easy_init();
+
+    checked_curl_setopt(pCurl, CURLOPT_NOSIGNAL, 1);
+    checked_curl_setopt(pCurl, CURLOPT_CONNECTTIMEOUT, config.connect_timeout); // For connection phase
+    checked_curl_setopt(pCurl, CURLOPT_TIMEOUT, config.timeout);                // For data transfer phase
+    checked_curl_setopt(pCurl, CURLOPT_ERRORBUFFER, errbuf);
+    checked_curl_setopt(pCurl, CURLOPT_WRITEFUNCTION, write_callback);
+    checked_curl_setopt(pCurl, CURLOPT_WRITEDATA, &res.body);
+    checked_curl_setopt(pCurl, CURLOPT_URL, url.c_str());
+    checked_curl_setopt(pCurl, CURLOPT_HEADERFUNCTION, header_callback);
+    checked_curl_setopt(pCurl, CURLOPT_HEADERDATA, &res.headers);
+
+    if (!user.empty() && !password.empty())
+    {
+        checked_curl_setopt(pCurl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
+        checked_curl_setopt(pCurl, CURLOPT_USERPWD, (user + ":" + password).c_str());
+    }
+
+    long code = 0;      // needs to be a long
+
+    if (curl_easy_perform(pCurl) == CURLE_OK)
+    {
+        curl_easy_getinfo(pCurl, CURLINFO_RESPONSE_CODE, &code);
+        res.code = code;
+    }
+    else
+    {
+        res.code = -1;
+        res.body = errbuf;
+    }
+
+    curl_easy_cleanup(pCurl);
+
+    return std::move(res);
+}
+
+}
+
+}