ephemerup

ephemerup

Simple standalone file upload server with expiration and commandline client.

Introduction

ephemerup is a simple standalone file server where every uploaded file expires sooner or later. The server provides a RESTful API and can be used easily with the commandline client upctl.

The idea is to provide a way to quickly exchange files between parties when no other way is available and the files themselfes are not important enough to keep them around. Think of this szenario: you're working for the network departement and there's a problem with your routing. Tech support asks you to create a network trace and send it to them. But you can't because the trace file is too large and sensitive to be sent by email. This is where ephemerup comes to the rescue.

You upload the file, send the download url to the other party and - assuming you've utilized the defaults - when they download it, it is being deleted immediately from the server. But you can also set an expire time, say 5 days or something like that.

The download urls generated by ephemerup consist of a unique onetime hash, so they are somewhat confident. However, if you're uploading really sensitive data, you better encrypt it.

ephemerup also supports something we call an API Context. There can be many such API contexts. Each of these has an associated token, which has to be used by legitimate clients to authenticate and authorize. A user can only manage uploads within that context. Think "tenant" if you will.

Demo

Features

• RESTful API
• Authentication and Authorization through bearer api token
• multiple tenants supported (tenant == api context)
• Each upload gets its own unique id
• download uri is public, no api required, it is intended for end users
• uploads may consist of one or multiple files
• zipped automatically
• uploads expire, either as soon as it gets downloaded or when a timer runs out
• the command line client uses the api
• configuration using HCL language
• docker container build available
• the server supports config by config file, environment variables or flags
• restrictive defaults

Installation

Since the software is currently being developed, there are no binary releases available yet. You'll need a go build environment. Just run make to build everything.

There's a Dockerfile available for the server so you can build and run it using docker:

make buildimage
docker-compose run ephemerup

Then use the client to test it.

Server Usage

ephemerupd -h
      --apikeys strings     Api key[s] to allow access
  -a, --apiprefix string    API endpoint path (default "/api")
  -n, --appname string      App name to say hi as (default "ephemerupd v0.0.1")
  -b, --bodylimit int       Max allowed upload size in bytes (default 10250000000)
  -c, --config string       custom config file
  -D, --dbfile string       Bold database file to use (default "/tmp/uploads.db")
  -d, --debug               Enable debugging
      --frontpage string    Content or filename to be displayed on / in case someone visits (default "welcome to upload api, use /api enpoint!")
  -4, --ipv4                Only listen on ipv4
  -6, --ipv6                Only listen on ipv6
  -l, --listen string       listen to custom ip:port (use [ip]:port for ipv6) (default ":8080")
  -p, --prefork             Prefork server threads
  -s, --storagedir string   storage directory for uploaded files (default "/tmp")
      --super string        The API Context which has permissions on all contexts
  -u, --url string          HTTP endpoint w/o path
  -v, --version             Print program version

All flags can be set using environment variables, prefix the flag with EPHEMERUPD_ and uppercase it, eg:

EPHEMERUPD_LISTEN=:8080

In addition it is possible to set api contexts using env vars (otherwise only possible using the config file):

EPHEMERUPD_CONTEXT_SUPPORT="support:tymag-fycyh-gymof-dysuf-doseb-puxyx"
EPHEMERUPD_CONTEXT_FOOBAR="foobar:U3VuIE1hciAxOSAxMjoyNTo1NyBQTSBDRVQgMjAyMwo"

Configuration can also be done using a config file (searched in the following locations):

• /etc/ephemerupd.hcl
• /usr/local/etc/ephemerupd.hcl
• ~/.config/ephemerupd/ephemerupd.hcl
• ~/.ephemerupd
• $(pwd)/ephemerupd.hcl

Or using the flag -c. Sample config file:

listen = ":8080"
bodylimit = 10000

apicontext = [
  {
    context = "root"
    key = "0fddbff5d8010f81cd28a7d77f3e38981b13d6164c2fd6e1c3f60a4287630c37",
  },
  {
    context = "foo",
    key = "970b391f22f515d96b3e9b86a2c62c627968828e47b356994d2e583188b4190a"
  }
]

#url = "https://sokrates.daemon.de"

# this is the root context with all permissions
super = "root"

Server endpoint

The server serves the API under the following endpoint: http://SERVERNAME[:PORT]/api/v1 where SERVERNAME[:PORT] is the argument to the -l commandline argument or the config option listen or the environment variable EPHEMERUPD_LISTEN.

By default the server listens on any interface ip4 and ipv6 on TCP port 8080. You can specify a server name or an ipaddress and a port. The server can be configured to run on ipv6 (or ipv4) only using the -4 respective the -6 commandline flags.

It does not support TLS at the moment. Use a nginx reverse proxy in front of it.

Server REST API

Every endpoint returns a JSON object. Each returned object contains the data requested plus:

• success: true or false
• code: HTTP Response Code
• message: error message, if success==false

Endpoints

Consumer URLs

The following endpoints are no API urls, but accessed directly by consumers using their browser or wget etc:

API Objects

Response:

Upload:

Form:

Note: if the expire field for a form is not set or set to "asap" only 1 upload object can be created from it. However, if a duration has been specified, the form can be used multiple times and thus creates multiple upload objects.

Client Usage

upctl 
Error: No command specified!
Usage:
  upctl [options] [flags]
  upctl [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  delete      Delete an upload
  describe    Describe an upload.
  download    Download a file.
  form        Form commands
  help        Help about any command
  list        List uploads
  upload      Upload files

Flags:
  -a, --apikey string     Api key to use
  -c, --config string     custom config file
  -d, --debug             Enable debugging
  -p, --endpoint string   upload api endpoint url (default "http://localhost:8080/api/v1")
  -h, --help              help for upctl
  -r, --retries int       How often shall we retry to access our endpoint (default 3)
  -v, --version           Print program version

Use "upctl [command] --help" for more information about a command.

The client must be configured using a config file. The following locations are searched for it:

• $(pwd)/upctl.hcl
• ~/.config/upctl/upctl.hcl

Sample config file for a client:

endpoint = "http://localhost:8080/api/v1"
apikey = "970b391f22f515d96b3e9b86a2c62c627968828e47b356994d2e583188b4190a"

The endpoint is the ephemerup server running somewhere and the apikey is the token you got from the server operator..

TODO

• add metrics (as in https://github.com/ansrivas/fiberprometheus)
• do not manually generate output urls, use fiber.GetRoute()
• upd: https://docs.gofiber.io/guide/error-handling/ to always use json output
• add (default by time!) sorting to list outputs, and add sort flag

BUGS

upctl HTTP 413 weird behavior

• with -d reports correctly the 413, w/o it, it reports the timeout before.

curl commands

upload

curl -X POST localhost:8080/api/putfile -F "upload[]=@xxx" -F "upload[]=@yyy" -H "Content-Type: multipart/form-data"

download

curl -O http://localhost:8080/api/v1/file/388f41f4-3f0d-41e1-a022-9132c0e9e16f/2023-02-28-18-33-xxx

delete

curl -X DELETE http://localhost:8080/api/v1/file/388f41f4-3f0d-41e1-a022-9132c0e9e16f/
curl -X DELETE http://localhost:8080/api/v1/file/?id=388f41f4-3f0d-41e1-a022-9132c0e9e16f/
curl -X DELETE -H "Accept: application/json"  -d '{"id":"$id"}' http://localhost:8080/api/v1/file/