[BUG][cpp-restsdk][csharp-nancfx] Multiple bugs in C# NancyFx and C++ REST SDK

[tzickel]

I hope it's OK I'm reporting all the issues I've found this way. It is my knowledge that non of them has been previously reported. Tested them all with OpenAPI 2.

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Framework: C# NancyFx
Problem: When returning 204 http status code, it explicitly returns an empty Content-Type header instead of not putting one at all, and returns 200 instead.
Severity: The empty Content-Type on 204 causes the c++ restsdk client to throw an exception because of this.
Temporary workaround: find "autogen_path" -iname "*.cs" | xargs -I {} sed -i 's/return new Response { ContentType = ""};/return new Response { ContentType = null, StatusCode = HttpStatusCode.NoContent };/g' {}

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Framework: C# NancyFx
Problem: When defining a property as an integer data type limited by specific enums, instead of returning the enum value, it returns it's enum index which is nonsense.
Severity: Can't define enums for integer types.
Temporary workaround: Defining and registering a custom NancyFx JavaScriptPrimitiveConverter which goes around it.

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Framework: C# NancyFx
Problem: Returning a binary string ("application/octet-stream") defines an C# Stream as the result, but NancyFx does not know how to handle it and borks with an error.
Severity: Can't return binary data.
Temporary workaround: Defining an custom NancyFx IResponseProcessor for application/octet-stream which streams the returned Stream.

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Framework: C# NancyFx
Problem: No automatic way to handle multiple produces.
Severity: Can't use multiple produces.
Temporary workaround: You can override the routing code for a specific endpoint and make it call different functions per provides.

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Framework: C++ REST SDK
Problem: When receiving a binary string, HttpContent isn't allocated and the program crashes, also the header file points to the wrong location in the Model directory.
Severity: Can't receive binary strings, also runtime crash.
Temporary workaround:

find "autogen_path/api" -iname "*.h" | xargs -I {} sed -i 's/#include "HttpContent.h"/#include "..\/HttpContent.h"/g' {}
find "autogen_path/api" -iname "*.cpp" | xargs -I {} sed -i 's/std::shared_ptr<HttpContent> localVarResult;/std::shared_ptr<HttpContent> localVarResult(new HttpContent());/g' {}

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Framework: C++ REST SDK
Problem: When an property is defined as a double number, and has no decimal dot in the data, the generation ignores the value.
Severity: Can't accept double numbers without dots.
Temporary workaround: Fix bool ModelBase::fromJson( const web::json::value& val, double & outVal ) and bool ModelBase::fromJson( const web::json::value& val, float & outVal )

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Framework: C++ REST SDK
Problem: Instead of reusing the base http connection between requests, it creates a new one per function call.
Severity: Performence penalty, each function call sets up a new connection, no http keep-alive.
Temporary workaround: ?

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Framework: C++ REST SDK
Problem: Cannot define model names to start with a number (in some others you can, and they are renamed on the fly).
Severity: ?
Temporary workaround: Don't put a number in the start of the model name.

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Framework: C++ REST SDK
Problem: The CMake library for the auto generated model / api header files marks them as private and require manual adding them to parent project. Severity: ?
Temporary workaround: Manually include the required header files.

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Framework: C# NancyFx
Problem: Sometimes added ghost "using ;" to Modules files.
Severity: Code does not compile.
Temporary solution: bash find "autogen_path" -iname "*.cs" | xargs -I {} sed -i "s/using ;//g" {}

[wing328]

cc @ravinikam (2017/07) @stkrwork (2017/07) @etherealjoy (2018/02) @martindelille (2018/03) @muttleyxd (2019/08)