Add 'multipart/form-data' support for file uploads

[myall200]

Fixes #714

• Multipart/form-data is not rerouted (error 404) #714

Motivation

Introduce a support of file streaming (file uploads) via the gateway, without body content caching.
Current loading of entire body to a memory in Ocelot core is a source of errors, unstable responses because downstream services produce errors during long lasting operation of the request.

Proposed Changes

• add multipart/form-data support for file uploads

Related to

• Problem with forwarding body of post method over OCELOT to asp.net API #792
• Multipart/form-data is not rerouted (error 404) #714
• Support scheme in service discovery address #617
• Incorrect 502 status code of downstream service when response prematurely closed with 403 #1685

[raman-m]

Hi zenghao!
Thanks for your interest in Ocelot!

Why did you revert the changes by reverting commit?

Could you Sync fork please? There is no develop branch in the forked repo!

[raman-m]

Related to:

• Problem with forwarding body of post method over OCELOT to asp.net API #792
• Multipart/form-data is not rerouted (error 404) #714
• Support scheme in service discovery address #617
• Incorrect 502 status code of downstream service when response prematurely closed with 403 #1685

[raman-m]

@myall200 Hi Zenghao!
Do you have any intention of contributing to this feature further?

I hope, if we will have a pair programming sessions together, we could deliver full functioning feature and the PR could close the list of open issues.

Happy Friday!
Have a nice sunny weekend in China! 😉

[raman-m]

The feature branch (master) has been rebased onto ThreeMammals:develop!

---

I don't see develop branch in your fork! Your fork is too old.

Could you Sync fork please? So, new develop branch will occur with all top commits!

Could you add me as collaborator to your forked repo please? I will create develop branch and make it default.

---

There are 2 failed tests in the build:

• Scenario: should multiplex
• Scenario: should not multiplex

Fully qualified names:

• Ocelot.UnitTests.Multiplexing.MultiplexingMiddlewareTests.should_multiplex
• Ocelot.UnitTests.Multiplexing.MultiplexingMiddlewareTests.should_not_multiplex

Reason: [Incorrect Content-Type:]
I guess it won't be hard to fix these failed tests.

[raman-m]

$\color{red}{There\ are\ 2\ failed\ tests\ in\ the\ build!}$

$\color{red}{There\ are\ 2\ failed\ tests\ in\ the\ build!}$

Build: 1422

[raman-m]

@myall200 Hello Zenghao,
We've encountered several issues with your pull request (PR):

• There are merge conflicts within the PR.
• The source branch is currently set to master when it should be develop.
• Forked repo has no default branch with name develop
• The continuous integration (CI) build is unable to start due to the feature branch being outdated.
• The feature branch has not been rebased onto the upstream develop branch, resulting in missing commits.

Regarding the proposed changes, it appears we resolved the form data forwarding issue a year ago. I will mark the PR as a draft until you create a new one. Subsequently, I will determine further actions, but your prompt feedback would be appreciated.
@ggnaegi FYI

[raman-m]

@ggnaegi Thoughts?
What should we do with this PR?

I checked the multiplexer, and we're still not copying the Form property:

Ocelot/src/Ocelot/Multiplexer/MultiplexingMiddleware.cs

Lines 215 to 240 in 4730613

	var target = new DefaultHttpContext
	{
	Request =
	{
	Body = bodyStream,
	ContentLength = from.ContentLength,
	ContentType = from.ContentType,
	Host = from.Host,
	Method = from.Method,
	Path = from.Path,
	PathBase = from.PathBase,
	Protocol = from.Protocol,
	QueryString = from.QueryString,
	Scheme = from.Scheme,
	IsHttps = from.IsHttps,
	Query = new QueryCollection(new Dictionary<string, StringValues>(from.Query)),
	RouteValues = new(from.RouteValues),
	},
	Connection =
	{
	RemoteIpAddress = source.Connection.RemoteIpAddress,
	},
	RequestServices = source.RequestServices,
	RequestAborted = source.RequestAborted,
	User = source.User,
	};