Support multipart/form-data

[hatamiarash7]

Description

After this PR, we can send POST requests in multipart/form-data format. This allows users to test the upload process quickly.

http_post_body_multipart:
    prober: http
    timeout: 5s
    http:
      method: POST
      body_multipart:
        - type: "file"
          key: "file"
          value: "/files/body.txt"
        - type: "text"
          key: "name"
          value: "arash"

We can define text or file fields here.

---

Changes

• Support multipart for HTTP probe
• Update example file
• Update configuration document
• Add a new test for multipart form request

[hatamiarash7]

any update?

[hatamiarash7]

Hello

Do we have an update for this PR?

The latest changes have been synced and new tests have been added for multipart.

Unfortunately, the IPv6 tests did not pass, and #1342 will solve the problem. Otherwise, a separate update is needed.

[electron0zero]

this implementation and configuration feels a little awkward, can we make it simple and implement this with just one bool flag called multipart?

If the flag is set, you can just make the check multi-part. for text and data, you can use the existing Body and BodyFile config values?

this would make it easy to configure and simplify this implementation as well?

[hatamiarash7]

In a multipart request, submitting multiple files (not just one file or text) should be possible. This is not possible using Body and BodyFile.

[electron0zero]

I read up some literature more on the multipart, and I still don't understand this code.

type Multipart struct {
	Type  string `yaml:"type,omitempty"`
	Key   string `yaml:"key,omitempty"`
	Value string `yaml:"value,omitempty"`
} 

the part I am having hard time understanding is the why behind Multipart struct and the Type, and the Key and Value in it.

do you need multiple text fields? if yes, can you share more info on it?

I think it should be possible to have it something like. MultipartFiles []string, and pass multiple filenames for the multi-part check, and append them to the Body and use the Body or BodyText for the body text.

[hatamiarash7]

Imagine a scenario where two files and two texts are to be sent. Consider the following curl example:

curl --location 'https://domain.com' \
--form 'text-key-1="text-value-1"' \
--form 'text-key-2="text-value-2"' \
--form 'file-key-1=@"/files/file-1.jpeg"' \
--form 'file-key-2=@"/files/file-2.jpeg"'

If we want to implement something like this, we need a separate structure to set the Type (text/file), Key, and Value.

http_post_body_multipart:
  prober: http
  timeout: 5s
  http:
    method: POST
    body_multipart:
      - type: "text-key-1"
        key: "name"
        value: "text-value-1"
      - type: "text-key-2"
        key: "name"
        value: "text-value-2"
      - type: "file"
        key: "file-key-1"
        value: "/files/file-1.jpeg"
      - type: "file"
        key: "file-key-2"
        value: "/files/file-2.jpeg"

[electron0zero]

I think this test can also be simplified after the implementation is updated.

[hatamiarash7]

As explained in the previous comment, we need to be able to POST different files/text. For this purpose, the bodyMultipart variable has been defined and used in this test.

[electron0zero]

for CI failure: #1342 is merged, please rebase.

[hatamiarash7]

for CI failure: #1342 is merged, please rebase.

Rebased.