How do I pass POST payload? about down

[janko]

Passing form-encoded POST parameters can be done using the http.rb's :form option. Example:

require "down/http"
require "json"

io = Down::Http.open("https://httpbin.org/post", method: :post, form: { "foo" => "bar" })
JSON.parse(io.read)
# => {"args"=>{},
#     "data"=>"",
#     "files"=>{},
#     "form"=>{"foo"=>"bar"},
#     "headers"=>
#      {"Content-Length"=>"7",
#       "Content-Type"=>"application/x-www-form-urlencoded",
#       "Host"=>"httpbin.org",
#       "User-Agent"=>"Down/5.2.1",
#       "X-Amzn-Trace-Id"=>"Root=1-60abf327-318b8db9456ae63260a21bc9"},
#     "json"=>nil,
#     "origin"=>"83.240.62.43",
#     "url"=>"https://httpbin.org/post"}

[Nakilon]

Oh, and I see JSON example there too, thanks. Somehow couldn't find it neither in tests nor in the main README.

UPD: ah sure, because that's another gem...

[Nakilon]

So I've got 411 Length Required (Down::ClientError). Passing "Content-Length" header didn't help, so I started a fake server to inspect the requests:

require "webrick"
require "pp"
WEBrick::HTTPServer.new(Port: 8080).tap{ |s|
  s.mount_proc("/"){ |req, res|
    pp req.header; res.body = "1"*1000 + "2"*2000
  }
}.start

require "down/http"
json = JSON.dump input
Down::Http.download(
  "http://localhost:8080/",
  headers: {
    "Authorization" => "bearer 123}",
    "Content-Length" => json.size
  },
  method: :post, body: json, max_size: 1000
).read

But it throws file is too large (max is 0MB) (Down::TooLarge) and I see no way to get those "first 1000 bytes" that I need. So maybe the down gem wasn't supposed to do such thing in the first place and I'm in the dead end? I just wanted to limit the download size.

UPD: I'll start it as another ticket if needed.

[jrochkind]

I don't think setting content-length on an HTTP request does what you think it does, just in terms of the HTTP protocol. I don't think you are encountering a bug in down. Also I don't think this is about passing a POST payload anymore?

If you want to download only the first 1000 bytes of a server response, my ideas would be to try to use HTTP Range headers (assuming the server supports this), or you can perhaps use down's streaming API to only read the first 1000 bytes, and discard the rest.

Setting content-length in a request is not a way to do what you want, that is not how it works according to the HTTP protocol. Content-length on a request must be the size of the request body. This is not about down, just about the HTTP protocol. Also, how to download only first 1000 bytes of a response is a different question than passing a POST payload, no?