Hello, I am creating a LMS that lets the user to download file. The user need the file should send me his token and after validating I let him download whatever he needs.
Now how can I stop user from downloading directly? because files are uploaded by admin in ftp, and ftp path is in my server
I don’t know where I can start?
Thanks
You can start by storing your files in your application in the assets folder then add authorization that only one type of user can download unlimited that file(ex: admin can download but user can’t).
If this scenario doesn’t work, then you can create a field in the user tables called plan. When a user pays you update the plan to paid. Then create a rule that only users with a paid plan can download files.
If you want to be even more specific then you will have to create another table with all the files structure like this:
Then create a join between the user tables with the files tables and verify each user to what file they belong
Also you will have to setup a payment system paypal stripe etc.
Also this link may provide some help Phoenix file download
I would “proxy” the download through phoenix…
user buys product - you persist purchase in DB
user hits /download_file/#{file_id}
phoenix verifies the login/session and purchase and then reads the file (or streams it) and sends it to the user
if you have multiple files just show a list of files and then the user can download on /download_file/#{file_id}
that way the user never gets a direct link and if the user shares the link /download_file/#{file_id} - the “stranger” clicking it will fail on having a session/logged in - and will fail on the purchase… so it doesnt work…
I think I need this lines of code. this is the place I can start.
conn |> put_resp_header("content-disposition", ~s(attachment; filename="#{filename}")) |> send_file(200, filename)
would you mind explaining me more pleas? the stream file can be attractive, I haven’t used it before (streams)
To protect files in the past (and will be likely how I will do it in an upcoming Phoenix app) would be similar to how I do it with other tech stacks. I let nginx deal with it for the most part, while still doing authentication / authorization within Phoenix.
I’d keep the protected files outside of the main static assets folder.
Then have an “internal” location block in my nginx config like this:
location /supersecrets/download/ {
internal;
alias /supersecrets/;
}
Then for the download route at the Phoenix level, I’d authorize the download with a token and before I send the response, I’d set the Content-Disposition, X-Accel-Redirect and Content-Type headers which basically tells Phoenix to let nginx serve the file.
Here’s what that looks like in Python:
response.headers['Content-Disposition'] = "attachment; filename=foo.zip"
response.headers['X-Accel-Redirect'] = '/supersecrets/download/foo.zip'
response.headers['Content-Type'] = 'application/octet-stream'
Of course you can change foo.zip to whatever file you’re serving.
I used this exact strategy like 5 years ago to serve a bunch of protected content and it held up very well.
Hello, Thanks
I use this code:
def download(conn, _params) do
file = File.read!("/Users/test/name.png")
conn
|> put_resp_content_type("image/png")
|> put_resp_header("Content-disposition","attachment; filename=\"test.png\"")
|> put_resp_header("X-Accel-Redirect", "/tempfile/download/test.png")
|> put_resp_header("Content-Type", "application/octet-stream")
|> send_resp(200, file)
end
I have a question , how can use File.stream! instead of File.read!. I want to create chunks what I need and send to my user
ASfter a google search found this
Sample code from the first link:
iex> stream = File.stream!("haiku.txt")
%File.Stream{
line_or_bytes: :line,
modes: [:raw, :read_ahead, :binary],
path: "haiku.txt",
raw: true
}
I saw these link before and test, but I had a error when I wanted to send file
file = stream = File.stream!("test.png")
conn
|> put_resp_content_type("image/png")
|> put_resp_header("Content-disposition","attachment; filename=\"test.png\"")
|> put_resp_header("X-Accel-Redirect", "/tempfile/download/test.png")
|> put_resp_header("Content-Type", "application/octet-stream")
|> send_resp(200, file)
send_resp has this error
no function clause matching in Plug.Conn.resp/3
if I change |> send_resp(200, file.path) it has no error but I couldn’t to create my chunk size and send to my user, and is it my file streams?
what about chunk?
I tested this code:
File.stream!("haiku.txt") |> Enum.with_index |> Enum.each(fn {content, _index} ->
****
end)
but I don’t know how can I change this line |> send_resp(200, file) that sends stream file to user download manager
Do you have a controller? or are you just trying to use static files?
Also here is a complete discussion on this https://github.com/phoenixframework/phoenix/issues/1786
Try the
send_chunked(200)
Seems like https://hexdocs.pm/plug/Plug.Conn.html#send_file/5 is the right call here. I see that this was tried earlier, what about it didn’t work?
I just have static files like png , mp4 and pdf format, I don’t know why Phoenix has no good doc for it, just can find this link
it can’t help me what to do!
I tested, but I can’t use it. I tried to find sample code 
please see this cod:
def download(conn, _params) do
file = File.stream!("/Users/shahryar/Desktop/Khat-Ghalam.png", [], 204800)
file |> Enum.with_index |> Enum.each(fn {content, _index} ->
conn
|> put_resp_content_type("image/png")
|> put_resp_header("Content-disposition","attachment; filename=\"test.png\"")
|> put_resp_header("X-Accel-Redirect", "/tempfile/download/test.png")
|> put_resp_header("Content-Type", "application/octet-stream")
|> send_resp(200, content)
# |> send_chunked(200)
end)
end
it works and the png file is healthy, but I don’t know Is it streams? I couldn’t use send_chunked(200)
HTTP/1.1 200 OK
Content-Type: image/png; charset=utf-8
Content-Disposition: attachment; filename="test.png"
x-xss-protection: 1; mode=block
Server: Cowboy
x-download-options: noopen
x-permitted-cross-domain-policies: none
Cache-Control: max-age=0, private, must-revalidate
cross-origin-window-policy: deny
Date: Fri, 05 Jul 2019 13:45:41 GMT
Content-Length: 10097
x-request-id: Fa6Gzp-CHY1D3jIAAHID
X-Accel-Redirect: /tempfile/download/test.png
x-content-type-options: nosniff
x-frame-options: SAMEORIGIN
[error] #PID<0.2222.0> running KhatoghalamWeb.Endpoint (connection #PID<0.2220.0>, stream id 1) terminated
Server: localhost:4000 (http)
Request: GET /download
** (exit) an exception was raised:
** (RuntimeError) expected action/2 to return a Plug.Conn, all plugs must receive a connection (conn) and return a connection, got: :ok
(khatoghalam) lib/khatoghalam_web/controllers/client_home_controller.ex:1: KhatoghalamWeb.ClientHomeController.phoenix_controller_pipeline/2
(phoenix) lib/phoenix/router.ex:280: Phoenix.Router.__call__/2
(khatoghalam) lib/khatoghalam_web/endpoint.ex:1: KhatoghalamWeb.Endpoint.plug_builder_call/2
(khatoghalam) lib/plug/debugger.ex:122: KhatoghalamWeb.Endpoint."call (overridable 3)"/2
(khatoghalam) lib/khatoghalam_web/endpoint.ex:1: KhatoghalamWeb.Endpoint.call/2
(phoenix) lib/phoenix/endpoint/cowboy2_handler.ex:33: Phoenix.Endpoint.Cowboy2Handler.init/2
(cowboy) /Applications/MAMP/htdocs/elixir-ex-source/khatoghalam/khatoghalam/deps/cowboy/src/cowboy_handler.erl:41: :cowboy_handler.execute/2
(cowboy) /Applications/MAMP/htdocs/elixir-ex-source/khatoghalam/khatoghalam/deps/cowboy/src/cowboy_stream_h.erl:296: :cowboy_stream_h.execute/3
(cowboy) /Applications/MAMP/htdocs/elixir-ex-source/khatoghalam/khatoghalam/deps/cowboy/src/cowboy_stream_h.erl:274: :cowboy_stream_h.request_process/3
(stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3
Here you can find a complete example of a working streaming app Very high memory usage when streaming file with Phoenix
this is not chunk file, it loads a file with url and load it and uses a module named HttpStream, I saw this repo https://github.com/Arquanite/phoenix-streaming-app. they didn’t chunk file to what size they need like custom size
I sent file to google drive like this
File.stream!(filepaths, [], chunk_size)
|> Enum.with_index
|> Enum.each(fn {content, _index} ->
# Process.sleep 2000
upload_content_to_google(flag, file_size, session_uri, content, chunk_size, email, file)
end)
and sender:
stat = HTTPoison.put(
"https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable&upload_id=#{session_uri}", # url
{:file, file_path} , # body
[
# header
{"Content-Length", "#{rest_chunk_size}"},
{"Content-Type", "application/tar"},
{"Content-Range", range}
],
[timeout: 50_000, recv_timeout: 50_000]
)
but that is upload. and that link you sent me it downloads on external link and runs with stream module , it doesn’t chunk file to many part with a size
maybe I can’t chunk my file to many parts and my user downloadsit , maybe the web server (ngnix) does it!!?
How about opening a new topic to attract more seasoned phoenix members with the following title:
How can I send a chunked file to a user?
Because at this moment i don’t know either.
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