From 20c454788f6099d32711abf652efdcc3fcaff66a Mon Sep 17 00:00:00 2001
From: Sam O'Connor <sam@octech.com.au>
Date: Mon, 19 Feb 2018 21:41:23 +1100
Subject: [PATCH] add DebugLayer / IODebug  <: IO, activated by verbose=3

---
 src/DebugRequest.jl | 32 ++++++++++++++++++++
 src/HTTP.jl         |  5 +++-
 src/IODebug.jl      | 71 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 107 insertions(+), 1 deletion(-)
 create mode 100644 src/DebugRequest.jl
 create mode 100644 src/IODebug.jl

diff --git a/src/DebugRequest.jl b/src/DebugRequest.jl
new file mode 100644
index 000000000..d8e2d692f
--- /dev/null
+++ b/src/DebugRequest.jl
@@ -0,0 +1,32 @@
+module DebugRequest
+
+import ..Layer, ..request
+using ..IOExtras
+import ..ConnectionPool: ByteView, byteview
+
+
+include("IODebug.jl")
+
+
+"""
+    request(DebugLayer, ::IO, ::Request, body) -> HTTP.Response
+
+Wrap the `IO` stream in an `IODebug` stream and print Message data.
+"""
+abstract type DebugLayer{Next <:Layer} <: Layer end
+export DebugLayer
+
+
+function request(::Type{DebugLayer{Next}}, io::IO, req, body; kw...) where Next
+
+    iod = IODebug(io)
+
+    try
+        return request(Next, iod, req, body; kw...)
+    finally
+        print(STDOUT, iod)
+    end
+end
+
+
+end # module DebugRequest
diff --git a/src/HTTP.jl b/src/HTTP.jl
index d71723ebf..2476ff721 100644
--- a/src/HTTP.jl
+++ b/src/HTTP.jl
@@ -423,6 +423,7 @@ include("ExceptionRequest.jl");         using .ExceptionRequest
                                         import .ExceptionRequest.StatusError
 include("RetryRequest.jl");             using .RetryRequest
 include("ConnectionRequest.jl");        using .ConnectionRequest
+include("DebugRequest.jl");             using .DebugRequest
 include("StreamRequest.jl");            using .StreamRequest
 include("ContentTypeRequest.jl");       using .ContentTypeDetection
 
@@ -545,6 +546,7 @@ function stack(;redirect=true,
                 status_exception=true,
                 readtimeout=0,
                 detect_content_type=false,
+                verbose=0,
                 kw...)
 
     NoLayer = Union
@@ -559,9 +561,10 @@ function stack(;redirect=true,
     (retry                ? RetryLayer                : NoLayer){
     (status_exception     ? ExceptionLayer            : NoLayer){
                             ConnectionPoolLayer{
+    (verbose >= 3         ? DebugLayer                : NoLayer){
     (readtimeout > 0      ? TimeoutLayer              : NoLayer){
                             StreamLayer
-    }}}}}}}}}}}
+    }}}}}}}}}}}}
 end
 
 include("client.jl")
diff --git a/src/IODebug.jl b/src/IODebug.jl
new file mode 100644
index 000000000..4cdd0b8d7
--- /dev/null
+++ b/src/IODebug.jl
@@ -0,0 +1,71 @@
+struct IODebug{T <: IO} <: IO
+    io::T
+    log::Vector{Tuple{String,String}}
+end
+
+IODebug(io::T) where T <: IO = IODebug{T}(io, [])
+
+logwrite(iod::IODebug, x) = push!(iod.log, ("➡️ ", x))
+logread(iod::IODebug, x) = push!(iod.log, ("⬅️ ", x))
+logunread(iod::IODebug, x) = push!(iod.log, ("♻️ ", x))
+ 
+Base.write(iod::IODebug, a...) = (logwrite(iod, join(a)); write(iod.io, a...))
+
+Base.write(iod::IODebug, x::String) = (logwrite(iod, x); write(iod.io, x))
+
+Base.unsafe_write(iod::IODebug, x::Ptr{UInt8}, n::UInt) =
+    (logwrite(iod, unsafe_string(x,n));
+     unsafe_write(iod.io, x, n))
+
+Base.read(iod::IODebug, n) =
+    (r = read(iod.io, n);
+     logread(iod, String(r)); r)
+
+Base.readavailable(iod::IODebug) =
+    (r = readavailable(iod.io);
+     logread(iod, String(r)); r)
+
+IOExtras.unread!(iod::IODebug, bytes) =
+    (logunread(iod, String(bytes));
+     unread!(iod.io, bytes))
+
+Base.eof(iod::IODebug) = eof(iod.io)
+Base.close(iod::IODebug) = close(iod.io)
+Base.isopen(iod::IODebug) = isopen(iod.io)
+Base.iswritable(iod::IODebug) = iswritable(iod.io)
+Base.isreadable(iod::IODebug) = isreadable(iod.io)
+IOExtras.startread(iod::IODebug) = startread(iod.io)
+IOExtras.startwrite(iod::IODebug) = startwrite(iod.io)
+IOExtras.closeread(iod::IODebug) = closeread(iod.io)
+IOExtras.closewrite(iod::IODebug) = closewrite(iod.io)
+
+@static if isdefined(Base, :bytesavailable)
+    Base.bytesavailable(iod::IODebug) = bytesavailable(iod.io)
+else
+    Base.nb_available(iod::IODebug) = nb_available(iod.io)
+end
+
+function Base.show(io::IO, iod::IODebug)
+    lock(io)
+    println(io, "$(typeof(iod)):\nio:     $(iod.io)")
+    prevop = ""
+    for (operation, bytes) in iod.log
+        if prevop != "" && prevop != operation
+            println(io)
+        end
+        prefix = rpad(operation, 5)
+        i = j = 1
+        while i < length(bytes)
+            j = findnext(bytes, '\n', i)
+            if j == nothing || j == 0
+                j = length(bytes)
+            end
+            println(io, prefix, "\"", escape_string(bytes[i:j]), "\"")
+            prefix = "    "
+            i = nextind(bytes, j)
+        end
+        prevop = operation
+    end
+    println(io)
+    unlock(io)
+end