I have a C++ program running on a server returning JSON formatted data, serialized with boost. In some cases one value part of a JSON packet is another JSON packet serialized to string. Running in XCode on my developing machine the program returns me the value data with escaped quotation marks, compiled on the Linux system without. Is there any way to force boost on linux to do that or a good workaround? (There was an error with missing value quotation marks in general that we already fixed).
Beneath is as an example the first line:
local:
"stations": "{n "area CHALLENGE_FUTURE": "{\n \"areaname CHALLENGE_FUTURE\": [...]"
online:
"stations": "{n "area CHALLENGE_FUTURE": "{\n "areaname CHALLENGE_FUTURE": [...]"
Boost version is 1.57, compiler (Local Xcode and Online Linux) is clang-linux-3.5. (see edit)
Here’s the simplified code:
// ----- STL
#include <iostream>
#include <string>
#include <map>
// ------ boost
#include <boost/asio.hpp>
#include <boost/foreach.hpp>
//formatter_base.hpp
//------------------------------------------------------------------------------
class formatter_base
{
protected:
std::map<std::string, std::string> datas;
public:
virtual ~formatter_base() {}
void setvalue(std::string key, std::string value)
{
datas[key] = value;
}
std::string getvalue(std::string key)
{
return datas[key];
}
bool containsKey(std::string key)
{
return (datas.find(key) != datas.end());
}
virtual void deserialize(char *data, const std::size_t size) = 0;
virtual std::string serialize(std::vector<std::string> keys) = 0;
};
//json_formatter.hpp
class json_formatter : public formatter_base
{
public:
virtual void deserialize(char *data, const std::size_t size);
virtual std::string serialize(std::vector<std::string> keys);
};
//datapacket.hpp
//------------------------------------------------------------------------------
class server;
extern server *tcp_server;
class datapacket
{
static const char id[4];
public:
enum DataFormat { BINARY = 0, JSON, XML };
std::string ip;
bool useHeader;
datapacket() : useHeader(false), packet_data(NULL) {}
datapacket(DataFormat format);
std::vector<char> process(char *data, std::size_t size, std::string ip);
std::string getvalue(std::string key)
{
return packet_data->getvalue(key);
}
void setvalue(std::string key, std::string value)
{
packet_data->setvalue(key, value);
}
bool containsKey(std::string key)
{
return packet_data->containsKey(key);
}
std::vector<char> serialize();
std::string toString();
private:
bool deserialize(char *data, std::size_t size);
std::string serialize_data(std::vector<std::string> keys);
formatter_base *packet_data;
};
//datapacket.cpp
//------------------------------------------------------------------------------
#include <boost/iostreams/stream.hpp>
#include <boost/foreach.hpp>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
#include <string.h>
datapacket::datapacket(DataFormat format)
: useHeader(false)
{
if(format == JSON)
{
packet_data = new json_formatter();
}
else
{
packet_data = NULL;
}
}
std::vector<char> datapacket::process(
char *data, std::size_t size, std::string ip)
{
//std::cout << "datapacket::process" << std::endl;
this->ip = ip;
std::vector<char> ret;
if (!deserialize(data, size))
return ret;
std::vector<std::string> keys;
std::string result;
/*extern void process(datapacket& gamedata);
process(*this);*/
ret.push_back('a');
ret.push_back('c');
ret.push_back('k');
return ret;
}
bool datapacket::deserialize(char *data, std::size_t size)
{
packet_data = new json_formatter();
packet_data->deserialize(data, size);
return true;
}
std::string datapacket::serialize_data(std::vector<std::string> keys)
{
return packet_data->serialize(keys);
}
std::vector<char> datapacket::serialize()
{
std::vector<std::string> keys;
std::string str = serialize_data(keys);
std::vector<char> ret;
ret.assign(str.begin(), str.end());
return ret;
}
std::string datapacket::toString()
{
std::vector<std::string> keys;
std::string str = serialize_data(keys);
return str;
}
//json_formatter.cpp
//------------------------------------------------------------------------------
using namespace boost::property_tree;
void json_formatter::deserialize(char *data, const std::size_t size)
{
std::stringstream ss;
ss.write(data, size);
// std::cout << "ss: " << ss.str() << std::endl;
ptree pt;
read_json(ss, pt);
BOOST_FOREACH(ptree::value_type &v, pt)
{
//log all received data
//std::cout << v.first.data() << ": " << v.second.data() << std::endl;
datas[v.first.data()] = v.second.data();
}
}
///-workaround 1.57 json
template <typename T>
struct my_id_translator
{
typedef T internal_type;
typedef T external_type;
boost::optional<T> get_value(const T &v) { return v.substr(1, v.size() - 2) ; }
boost::optional<T> put_value(const T &v) { return '"' + v + '"'; }
};
///
std::string json_formatter::serialize(std::vector<std::string> keys)
{
ptree pt;
if(keys.empty())
{
typedef std::map<std::string, std::string> mapType;
BOOST_FOREACH(const mapType::value_type& myPair, datas)
{
//workaround for wrong formatted string
if((BOOST_VERSION == 105700) && (BOOST_OS_LINUX))
{
//1.57
pt.put(myPair.first, myPair.second, my_id_translator<std::string>());
}
else
{
//1.54
pt.put(myPair.first, myPair.second);
}
//std::cout << myPair.first << ": " << myPair.second << std::endl;
}
}
else
{
BOOST_FOREACH(std::string key, keys)
{
//workaround for wrong formatted string
if(BOOST_VERSION == 105700)
{
#if BOOST_OS_LINUX
pt.put(key, """ + datas[key] + """, my_id_translator<std::string>());
#else
pt.put(key, datas[key], my_id_translator<std::string>());
#endif
}
else
{
pt.put(key, datas[key]);
}
// std::cout << key << ": " << datas[key] << std::endl;
}
}
std::stringstream ss;
write_json(ss, pt);
std::string str = ss.str();
// WORKAROUND
// Replace all escaped backslashes
// This was because some clients couldn't interpret "command\/read"
std::string oldStr = "\/";
std::string newStr = "/";
std::size_t pos = 0;
while((pos = str.find(oldStr)) != std::string::npos){
str = str.replace(pos, oldStr.length(), newStr);
pos += newStr.length();
}
// /WORKAROUND
//std::cout << "Serialize message:" << std::endl;
//std::cout << str << std::endl;
return str;
}
//main.cpp
//------------------------------------------------------------------------------
class dataClass
{
public:
dataClass() {}
std::string name;
};
class innerDataClass
{
public:
innerDataClass() {}
std::string name;
int score;
std::string baseClassName;
};
using boost::asio::ip::tcp;
namespace stdpatch
{
template <typename T> std::string to_string(const T& n)
{
std::ostringstream stm;
stm << n;
return stm.str();
}
}
std::map<std::string, dataClass> listDC;
std::map<std::string, innerDataClass> listIDC;
void Init()
{
//Some initial values
dataClass d1; d1.name = "dataClass1"; listDC["d1"] = d1;
dataClass d2; d2.name = "dataClass2"; listDC["d2"] = d2;
innerDataClass i1; i1.name = "innerClass1"; i1.baseClassName = "dataClass1";
i1.score = 5; listIDC["i1"] = i1;
innerDataClass i2; i2.name = "innerClass2"; i2.baseClassName = "dataClass1";
i1.score = 21; listIDC["i2"] = i2;
innerDataClass i3; i3.name = "innerClass3"; i1.baseClassName = "dataClass2";
i1.score = 1; listIDC["i3"] = i3;
}
//returns JSON
datapacket GetJSON()
{
std::pair<std::string, dataClass> baseClassPair;
std::pair<std::string, innerDataClass> innerClassPair;
datapacket baseClasses (datapacket::JSON);
baseClasses.setvalue("comment", "this holds all the base classes");
BOOST_FOREACH(baseClassPair, listDC)
{
datapacket baseClassData (datapacket::JSON);
baseClassData.setvalue("dataName", baseClassPair.first);
BOOST_FOREACH(innerClassPair, listIDC)
{
if (innerClassPair.second.baseClassName == baseClassPair.second.name)
{
datapacket innerClassData (datapacket::JSON);
innerClassData.setvalue(
"name", innerClassPair.second.name);
innerClassData.setvalue(
"score", stdpatch::to_string(innerClassPair.second.score));
baseClassData.setvalue(
"inner " + innerClassPair.first, innerClassData.toString());
}
}
baseClasses.setvalue("base " + baseClassPair.first, baseClassData.toString());
}
datapacket packet (datapacket::JSON);
packet.setvalue("comment", "this is the base-packet");
packet.setvalue("baseClasses", baseClasses.toString());
return packet;
}
int main(int argc, char* argv[])
{
Init();
datapacket packet (datapacket::JSON);
packet = GetJSON();
std::cout << std::endl << std::endl
<< "------------- RESULT --------------"
<< std::endl << std::endl;
std::cout << packet.toString() << std::endl;
return 0;
}
The expected output should be:
------------- RESULT --------------
baseClasses: {
"base d1": "{n "dataName": "d1",n "inner i1": "{\n \"gameID\": \"5\",\n \"name\": \"innerClass1\"\n}\n",n "inner i2": "{\n \"gameID\": \"1989860191\",\n \"name\": \"innerClass2\"\n}\n"n}n",
"base d2": "{n "dataName": "d2"n}n",
"comment": "this holds all the base classes"
}
comment: this is the base-packet
{
"baseClasses": "{n "base d1": "{\n \"dataName\": \"d1\",\n \"inner i1\": \"{\\n \\\"gameID\\\": \\\"5\\\",\\n \\\"name\\\": \\\"innerClass1\\\"\\n}\\n\",\n \"inner i2\": \"{\\n \\\"gameID\\\": \\\"1989860191\\\",\\n \\\"name\\\": \\\"innerClass2\\\"\\n}\\n\"\n}\n",n "base d2": "{\n \"dataName\": \"d2\"\n}\n",n "comment": "this holds all the base classes"n}n",
"comment": "this is the base-packet"
}
but the quotation marks are unescaped in my servers case:
comment: this is the base-packet
{
"baseClasses": "{n "base d1": "{\n "dataName": "d1",\n "inner i1": "{\\n "gameID": "5",\\n "name": "innerClass1"\\n}\\n",\n "inner i2": "{\\n "gameID": "1989860191",\\n "name": "innerClass2"\\n}\\n"\n}\n",n "base d2": "{\n \"dataName": "d2"\n}\n",n "comment": "this holds all the base classes"n}n",
"comment": "this is the base-packet"
}
To test wether the problem is within write_json or the transit I made a simple JSON package:
datapacket testData(datapacket::JSON);
testData.setvalue("text", ""world"");
testData.setvalue("inner1", testData.toString());
testData.setvalue("inner2", testData.toString());
The results are the following:
XCode:
{
"inner1": "{n "text": "\"world\""n}n",
"inner2": "{n "inner1": "{\n \"text\": \"\\\"world\\\"\"\n}\n",n "text": "\"world\""n}n",
"text": ""world""
}
Server:
{
"inner1": "{n "text": ""world""n}n"
"inner2": "{n "text": ""world"",n "inner1": "{\n "text": ""world""\n}\n"n}n",
"text": ""world""
}
This should show that the problem is within the write_json
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Answer
This might be the silliest error ever: After weeks of tracing the error down, we’ve found out that the linux compiling shell script we’ve used to build the project on our machine manually changed the JSON parsing behaviour. If for all we’ve learned something from this, it is: Never trust stuff you’ve copied from the internet.