# HTTP.jl client layer
**URL:** https://discourse.julialang.org/t/http-jl-client-layer/128098
**Category:** General Usage
**Tags:** http
**Created:** [April 15, 2025, 1:51pm UTC](https://discourse.julialang.org/t/http-jl-client-layer/128098 "2025-04-15T13:51:31Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [April 15, 2025, 1:51pm UTC](https://discourse.julialang.org/t/http-jl-client-layer/128098/1 "2025-04-15T13:51:31Z")
I’m trying to implement an auth layer for HTTP.jl
```julia
module ApiClient
import HTTP
import Dates
import JSON
Base.@kwdef struct TokenInfo
access_token::String = ""
expires_at::Dates.DateTime = Dates.now(Dates.UTC) + Dates.Second(0)
token_type::String = "Bearer"
end
struct JWTConfig
client_id::String
client_secret::String
token_url::String
token_info::Ref{TokenInfo}
end
function getToken(jwt_config::JWTConfig)
response = HTTP.post(
jwt_config.token_url,
["Content-Type" => "application/json"],
JSON.json(
Dict(
"grant_type" => "client_credentials",
"client_id" => jwt_config.client_id,
"client_secret" => jwt_config.client_secret,
),
),
)
response_data = JSON.parse(String(response.body))
return TokenInfo(
response_data["access_token"],
Dates.now(Dates.UTC) + Dates.Second(response_data["expires_in"]),
response_data["token_type"],
)
end
function AuthLayer(handler)
# return handler function
return function (req; jwt_config::JWTConfig, kwargs...)
# we add a custom header with stringified auth creds
try
# Try the original request
HTTP.setheader(req, "Authorization" => "Bearer $(jwt_config.token_info[].access_token)")
return handler(req; kwargs...)
catch e
# Check if it's a 401 error
if e isa HTTP.StatusError && e.status == 401
# Refresh the token and retry the request
jwt_config.token_info[] = getToken(jwt_config)
HTTP.setheader(req, "Authorization" => "Bearer $(jwt_config.token_info[].access_token)")
try
return handler(req; kwargs...)
catch
throw(e)
end
else
# If it's not a 401 error, rethrow the exception
throw(e)
end
end
end
end
HTTP.@client [AuthLayer]
end
```
But somehow this does not work correctly. I can access the token and resource I want, but when I first access the token I get half the response (literary the JSON body is cut off). If I switch on debugging I see, that the HTTP response is weird with many fields doubled, e.g. two times `Content-Length: 107` and `Content-Length: 26699`.
How can I call the token requresh url when a request fails? Is this not supported?
---
### Author:  [@quinnj](https://discourse.julialang.org/u/quinnj)
#### Post date: [April 15, 2025, 2:00pm UTC](https://discourse.julialang.org/t/http-jl-client-layer/128098/2 "2025-04-15T14:00:06Z")
Sorry for a bit of a rushed response, but yes, it can be a little tricky when trying to retry requests like this. You can check out some of the machinery we use/do in the RetryRequest layer here: [HTTP.jl/src/clientlayers/RetryRequest.jl at ef9a169c5471e14558409a649057d773c09451f6 · JuliaWeb/HTTP.jl · GitHub](https://github.com/JuliaWeb/HTTP.jl/blob/ef9a169c5471e14558409a649057d773c09451f6/src/clientlayers/RetryRequest.jl#L63)
---
### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [April 15, 2025, 2:04pm UTC](https://discourse.julialang.org/t/http-jl-client-layer/128098/3 "2025-04-15T14:04:53Z")
```julia
function AuthLayer(handler)
# return handler function
return function (req; jwt_config::JWTConfig, kwargs...)
try
# Try the original request
HTTP.setheader(req, "Authorization" => "Bearer $(jwt_config.token_info[].access_token)")
return handler(req; kwargs...)
catch e
# Check if it's a 401 error
if e isa HTTP.StatusError && e.status == 401
HTTP.reset!(req.response) # reset the original request for retry
# Refresh the token and retry the request
jwt_config.token_info[] = getToken(jwt_config)
HTTP.setheader(req, "Authorization" => "Bearer $(jwt_config.token_info[].access_token)")
try
return handler(req; kwargs...)
catch
throw(e)
end
else
# If it's not a 401 error, rethrow the exception
throw(e)
end
end
end
end
```
---
### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [May 6, 2025, 2:40pm UTC](https://discourse.julialang.org/t/http-jl-client-layer/128098/4 "2025-05-06T14:40:47Z")
@quinnj I wanted to have the auth layer as the last one but I get an error:
```julia
HTTP.@client (last = AuthLayer) ()
```
```julia
ERROR: MethodError: no method matching keys(::typeof(ApiClient.AuthLayer))
The function `keys` exists, but no method is defined for this combination of argument types.
Closest candidates are:
keys(::MathOptInterface.Utilities.IndexMap)
@ MathOptInterface C:\JuliaPackages\packages\MathOptInterface\JdLrc\src\Utilities\copy\index_map.jl:98
keys(::Base.TermInfo)
@ Base terminfo.jl:232
keys(::LibPQ.PQConversions)
@ LibPQ C:\JuliaPackages\packages\LibPQ\i4yBe\src\typemaps.jl:259
...
Stacktrace:
[1] eachindex(itrs::Function)
@ Base .\abstractarray.jl:318
[2] iterate(A::Base.Iterators.Reverse{typeof(ApiClient.AuthLayer)})
@ Base.Iterators .\iterators.jl:143
[3] _foldl_impl(op::Base.BottomRF{…}, init::Function, itr::Base.Iterators.Reverse{…})
@ Base .\reduce.jl:56
[4] foldl_impl(op::Base.BottomRF{…}, nt::Function, itr::Base.Iterators.Reverse{…})
@ Base .\reduce.jl:48
[5] mapfoldr_impl(f::Function, op::Function, nt::Function, itr::Function)
@ Base .\reduce.jl:204
[6] mapfoldr(f::Function, op::Function, itr::Function; init::Function)
@ Base .\reduce.jl:223
[7] foldr(op::Function, itr::Function; kw::@Kwargs{init::HTTP.ConnectionRequest.var"#connections#4"{…}})
@ Base .\reduce.jl:242
[8] stack(observelayers::Bool, requestlayers::Function, streamlayers::Tuple{})
@ HTTP C:\JuliaPackages\packages\HTTP\MIUdD\src\HTTP.jl:447
```
---
### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [May 6, 2025, 2:44pm UTC](https://discourse.julialang.org/t/http-jl-client-layer/128098/5 "2025-05-06T14:44:21Z")
Sry, my bad!
> **[API Reference · HTTP.jl](https://juliaweb.github.io/HTTP.jl/stable/reference/#HTTP.%40client)**
> a NamedTuple with keys `first` and `last` can be provided with values being a **collection** of layers.
```julia
HTTP.@client (last = [AuthLayer]) ()
```