Merge branch 'master' of git.niklashalle.net:n_core into HEAD

6 files changed, 186 insertions, 4 deletions

diff --git a/README.md b/README.md
index c132183..c59ecd4 100644
--- a/README.md
+++ b/README.md
@@ -74,10 +74,15 @@ No extra content.
 The text should be printed underlined.  
 No extra content.  
   
+##### `attachment`
+The text is the caption of an attached file.
+Extra content: String of content: "`file_name`;`file_type`;`file_content`", where `file_content` is base64 encoded.  
+E.g.: "image.png;png;iVBORw0KGgoAAAANSUhEUgAAABwAAAAMBAMAAACD9cA8AAAALVBMVEX///8AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADAOrOgAAAADnRSTlMAELt2Mu9Eic1mIqtU3XZzvlQAAAAJcEhZcwAADsQAAA7EAZUrDhsAAACJSURBVAgdY2BgFGCAARCTyQDGAzP5HOBcENMVzgMx0zsqGXjmGDBwzpwFYjJoMjBsZkhjOMlQCWIyvGLgvMBQxVDhIABkMrAFMPDqTE5gWPv0AJDJwL6BQW4ByLTlD4BMBo4JMnJADscBhgAgk4HXwYDXgeEINwMbkDZg4LFZwFVzUoAt5ySICQDlYB5evEnwqgAAAABJRU5ErkJggg=="  
+  
 ##### `command`
-The text should be formated in a way to underlying platform of the bridge would recognize it (e.g. prefix with '/').  
+The text should be formatted in a way to underlying platform of the bridge would recognize it (e.g. prefix with '/').  
 Extra content: the description of the command.  
   
 ##### `link`
 The text should be formatted as a link.  
-Extra content: the alt text for the uri - the uri should be the text itself, so that clients ignoring this annotation still show the real uri.
+Extra content: the alt text for the uri - the uri should be the text itself, so that clients ignoring this annotation still show the real uri.
\ No newline at end of file
diff --git a/include/AnnotationTypes.hpp b/include/AnnotationTypes.hpp
index 66d0b9d..8fba983 100644
--- a/include/AnnotationTypes.hpp
+++ b/include/AnnotationTypes.hpp
@@ -14,6 +14,7 @@ namespace Reply {
             DECL_ENUM_ELEMENT(none),
             DECL_ENUM_ELEMENT(bold),
             DECL_ENUM_ELEMENT(italics),
+            DECL_ENUM_ELEMENT(attachment),
             DECL_ENUM_ELEMENT(strikethrough),
             DECL_ENUM_ELEMENT(underline),
             DECL_ENUM_ELEMENT(command),
diff --git a/include/SimpleHandlers.hpp b/include/SimpleHandlers.hpp
index aef2372..1121685 100644
--- a/include/SimpleHandlers.hpp
+++ b/include/SimpleHandlers.hpp
@@ -11,5 +11,7 @@ namespace Handler {
 
     json wikiHandler(std::string const &arguments, std::string const &session, void *payload);
 
+    json latexRenderHandler(std::string const &arguments, std::string const &session, void *payload);
+
     json klingerHandler(std::string const &arguments, std::string const &session, void *payload);
 }
\ No newline at end of file
diff --git a/src/Response.cpp b/src/Response.cpp
index 286de52..53b0d8c 100644
--- a/src/Response.cpp
+++ b/src/Response.cpp
@@ -44,4 +44,4 @@ Response::json Response::create_response(std::vector<json> &&reply, std::string
     response["session"] = session;
     response["reply"] = std::move(reply);
     return response;
-}
\ No newline at end of file
+}
diff --git a/src/SimpleHandlers.cpp b/src/SimpleHandlers.cpp
index ee801d4..eba9331 100644
--- a/src/SimpleHandlers.cpp
+++ b/src/SimpleHandlers.cpp
@@ -2,7 +2,14 @@
 
 #include "Response.hpp"
 
-#include <fstream>
+#include <array>
+#include <cctype>
+#include <memory>
+#include <string>
+#include <iomanip>
+#include <sstream>
+#include <iostream>
+#include <stdexcept>
 
 using namespace Response;
 
@@ -87,3 +94,165 @@ json Handler::sayHandler(const std::string &arguments, const std::string &sessio
     (void) payload;
     return simple_response(arguments, session, true);
 }
+
+std::string url_encode(std::string const &value) {
+    std::ostringstream escaped;
+    escaped.fill('0');
+    escaped << std::hex;
+
+    for (char c : value) {
+        // Keep alphanumeric and other accepted characters intact
+        if (isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
+            escaped << c;
+            continue;
+        }
+
+        // Any other characters are percent-encoded
+        escaped << std::uppercase;
+        escaped << '%' << std::setw(2) << int((unsigned char) c);
+        escaped << std::nouppercase;
+    }
+
+    return escaped.str();
+}
+
+std::string exec(const char* cmd) {
+    std::array<char, 128> buffer{};
+    std::string result;
+    std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd, "r"), pclose);
+    if (!pipe) {
+        throw std::runtime_error("popen() failed!");
+    }
+    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
+        result += buffer.data();
+    }
+    return result;
+}
+
+static std::string const base64_chars =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+        "abcdefghijklmnopqrstuvwxyz"
+        "0123456789+/";
+
+std::string base64_encode(unsigned char const *input, unsigned int const len) {
+    std::string ret;
+    size_t i = 0;
+    unsigned char bytes[3];
+    unsigned char sextets[4];
+
+    while (i <= (len - 3)) {
+        bytes[0] = *(input++);
+        bytes[1] = *(input++);
+        bytes[2] = *(input++);
+
+        sextets[0] = (bytes[0] & 0xfc) >> 2;    // Cuts last two bits off of first byte
+        sextets[1] = ((bytes[0] & 0x03) << 4) + ((bytes[1] & 0xf0)
+                >> 4);   // Takes last two bits from first byte and adds it to first 4 bits of 2nd byte
+        sextets[2] = ((bytes[1] & 0x0f) << 2) + ((bytes[2] & 0xc0)
+                >> 6);   // Takes last 4 bits of 2nd byte and adds it to first 2 bits of third byte
+        sextets[3] = bytes[2] & 0x3f;   // takes last 6 bits of third byte
+
+        for (unsigned char sextet : sextets) {
+            ret += base64_chars[sextet];
+        }
+
+        i += 3; // increases to go to third byte
+    }
+
+    if (i != len) {
+        size_t k = 0;
+        size_t j = len - i; // Find index of last byte
+        while (k < j) {     // Sets first bytes
+            bytes[k] = *(input++);
+            ++k;
+        }
+
+        while (j < 3) {     // Set last bytes to 0x00
+            bytes[j] = '\0';
+            ++j;
+        }
+
+        sextets[0] = (bytes[0] & 0xfc) >> 2;    // Cuts last two bits off of first byte
+        sextets[1] = ((bytes[0] & 0x03) << 4) + ((bytes[1] & 0xf0)
+                >> 4);   // Takes last two bits from first byte and adds it to first 4 bits of 2nd byte
+        sextets[2] = ((bytes[1] & 0x0f) << 2) + ((bytes[2] & 0xc0)
+                >> 6);   // Takes last 4 bits of 2nd byte and adds it to first 2 bits of third byte
+        // No last one is needed, because if there were 4, then (i == len) == true
+
+        for (j = 0; j < (len - i) + 1; ++j) {   // Gets sextets that include data
+            ret += base64_chars[sextets[j]];    // Appends them to string
+        }
+
+        while ((j++) < 4)   // Appends remaining ='s
+            ret += '=';
+
+    }
+
+    return ret;
+}
+
+std::string base64_encode_file(std::string const &path) {
+    std::vector<char> temp;
+
+    std::ifstream infile;
+    infile.open(path, std::ios::binary);     // Open file in binary mode
+    if (infile.is_open()) {
+        while (!infile.eof()) {
+            char c = (char) infile.get();
+            temp.push_back(c);
+        }
+        infile.close();
+    } else {
+        std::cerr << path << " Error: " << strerror(errno) << std::endl;
+        return "File could not be opened";
+    }
+    std::string ret(temp.begin(), temp.end() - 1);
+    ret = base64_encode((unsigned const char *) ret.c_str(), ret.size());
+
+    return ret;
+}
+
+json Handler::latexRenderHandler(std::string const &arguments, std::string const &session, void *payload) {
+    (void) payload;
+
+    std::string png_file = exec("mktemp");
+    png_file.pop_back(); // remove trailing new line
+    std::string jpg_file = png_file + ".jpg";
+
+    //std::cout << ("png_file " + png_file) << exec(("png_file " + png_file).c_str()) << std::endl;
+
+    std::string result = exec(("curl -s 'https://latex.codecogs.com/png.latex?" + url_encode(arguments) + "' "
+            "-H 'User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0' "
+            "-H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8' "
+            "-H 'Accept-Language: en-US,en;q=0.5' --compressed -H 'DNT: 1' -H 'Connection: keep-alive' "
+            "-H 'Upgrade-Insecure-Requests: 1' --output " + png_file).c_str());
+
+    //std::cout << ("png_file " + png_file) << exec(("png_file " + png_file).c_str()) << std::endl;
+
+    if (!result.empty())
+        return simple_response("Error getting image: " + result + "\n"
+                                    "Please report to an admin", session, false);
+
+    // convert to jpg, mainly to loose background transparency ( :( ), so the images work in dark theme clients too
+    result = exec(("convert " + png_file + " " + jpg_file).c_str());
+
+    if (!result.empty())
+        return simple_response("Error converting image: " + result + "\n"
+                                    "Please report to an admin", session, false);
+
+    std::vector<json> reply_vec;
+    std::vector<json> annotations;
+
+    annotations.emplace_back(
+            create_annotation(
+                    Reply::AnnotationType::attachment,
+                    "latex.png;png;" + base64_encode_file(jpg_file)));
+
+    reply_vec.emplace_back(create_text("", std::move(annotations)));
+
+    // single shot try to remove the files
+    std::remove(jpg_file.c_str());
+    std::remove(png_file.c_str());
+
+    return create_response(std::move(reply_vec), session, true);
+}
diff --git a/src/main.cpp b/src/main.cpp
index db05590..6b3ceb3 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -40,6 +40,11 @@ int main() {
                         "{adlershof, nord, sued} Shows the daily menu of the mensa at various places.");
             }});
     regular_commands.emplace_back(
+            Handler::CommandHandler{"latex", Handler::latexRenderHandler, [createPlainDescriptionFromText]() {
+                return createPlainDescriptionFromText(
+                        "Renders the given string to a png");
+            }});
+    regular_commands.emplace_back(
             Handler::CommandHandler{"klinger", Handler::klingerHandler, [createPlainDescriptionFromText]() {
                 return createPlainDescriptionFromText("Greats in french. Bonjour!");
             }});