[BREAKING]: Change internal layers stack to be value-based instead of…

… type-based (#789)

Overhaul internal client-side "layers" to a more functional approach to simplify the interface for custom layers, refactor expected arguments to layers, and clarify abilities to modify the client-side stack: a more advanced option via pushlayer!/poplayer! to affect the global stack, and a more recommended @client macro to generate your own client that includes custom layers.

docs/src/internal_architecture.md

@@ -14,7 +14,6 @@ HTTP.BasicAuthLayer
 HTTP.CookieLayer
 HTTP.CanonicalizeLayer
 HTTP.MessageLayer
-HTTP.AWS4AuthLayer
 HTTP.RetryLayer
 HTTP.ExceptionLayer
 HTTP.ConnectionPoolLayer

src/BasicAuthRequest.jl

@@ -1,32 +1,27 @@
 module BasicAuthRequest
 
 using ..Base64
-
-import ..Layer, ..request
 using URIs
-using ..Pairs: getkv, setkv
+import ..Messages: setheader, hasheader
 import ..@debug, ..DEBUG_LEVEL
 
+export basicauthlayer
 """
-    request(BasicAuthLayer, method, ::URI, headers, body) -> HTTP.Response
+    basicauthlayer(req) -> HTTP.Response
 
 Add `Authorization: Basic` header using credentials from url userinfo.
 """
-abstract type BasicAuthLayer{Next <: Layer} <: Layer{Next} end
-export BasicAuthLayer
-
-function request(::Type{BasicAuthLayer{Next}},
-                 method::String, url::URI, headers, body; kw...) where Next
-
-    userinfo = unescapeuri(url.userinfo)
-
-    if !isempty(userinfo) && getkv(headers, "Authorization", "") == ""
-        @debug 1 "Adding Authorization: Basic header."
-        setkv(headers, "Authorization", "Basic $(base64encode(userinfo))")
+function basicauthlayer(handler)
+    return function(req; basicauth::Bool=true, kw...)
+        if basicauth
+            userinfo = unescapeuri(req.url.userinfo)
+            if !isempty(userinfo) && !hasheader(req.headers, "Authorization")
+                @debug 1 "Adding Authorization: Basic header."
+                setheader(req.headers, "Authorization" => "Basic $(base64encode(userinfo))")
+            end
+        end
+        return handler(req; kw...)
     end
-
-    return request(Next, method, url, headers, body; kw...)
 end
 
-
 end # module BasicAuthRequest

src/CanonicalizeRequest.jl

@@ -1,27 +1,26 @@
 module CanonicalizeRequest
 
-import ..Layer, ..request
 using ..Messages
 using ..Strings: tocameldash
 
+export canonicalizelayer
+
 """
-    request(CanonicalizeLayer, method, ::URI, headers, body) -> HTTP.Response
+    canonicalizelayer(req) -> HTTP.Response
 
 Rewrite request and response headers in Canonical-Camel-Dash-Format.
 """
-abstract type CanonicalizeLayer{Next <: Layer} <: Layer{Next} end
-export CanonicalizeLayer
-
-function request(::Type{CanonicalizeLayer{Next}},
-                 method::String, url, headers, body; kw...) where Next
-
-    headers = canonicalizeheaders(headers)
-
-    res = request(Next, method, url, headers, body; kw...)
-
-    res.headers = canonicalizeheaders(res.headers)
-
-    return res
+function canonicalizelayer(handler)
+    return function(req; canonicalize_headers::Bool=false, kw...)
+        if canonicalize_headers
+            req.headers = canonicalizeheaders(req.headers)
+        end
+        res = handler(req; kw...)
+        if canonicalize_headers
+            res.headers = canonicalizeheaders(res.headers)
+        end
+        return res
+    end
 end
 
 canonicalizeheaders(h::T) where {T} = T([tocameldash(k) => v for (k,v) in h])