ENH: provide "application/vnd.plotly.v1+json" for Plotly and PlotlyJS backends

For use in jupyterlab and nteract

closes #1418

closes #1386

src/Plots.jl

@@ -14,6 +14,7 @@ using Base.Meta
 @reexport using PlotThemes
 import Showoff
 import StatsBase
+import JSON
 
 using Requires
 

src/backends/plotly.jl

@@ -86,8 +86,6 @@ const _plotly_js_path_remote = "https://cdn.plot.ly/plotly-latest.min.js"
 
 function _initialize_backend(::PlotlyBackend; kw...)
   @eval begin
-    import JSON
-
     _js_code = open(readstring, _plotly_js_path, "r")
 
     # borrowed from https://github.com/plotly/plotly.py/blob/2594076e29584ede2d09f2aa40a8a195b3f3fc66/plotly/offline/offline.py#L64-L71 c/o @spencerlyon2
@@ -740,15 +738,17 @@ function plotly_hover!(d_out::KW, hover)
 end
 
 # get a list of dictionaries, each representing the series params
-function plotly_series_json(plt::Plot)
+function plotly_series(plt::Plot)
     slist = []
     for series in plt.series_list
         append!(slist, plotly_series(plt, series))
     end
-    JSON.json(slist)
+    slist
-    # JSON.json(map(series -> plotly_series(plt, series), plt.series_list))
 end
 
+# get json string for a list of dictionaries, each representing the series params
+plotly_series_json(plt::Plot) = JSON.json(plotly_series(plt))
+
 # ----------------------------------------------------------------
 
 const _use_remote = Ref(false)

src/output.jl

@@ -261,23 +261,47 @@ end
 @require IJulia begin
     if IJulia.inited
 
+        """
+        Add extra jupyter mimetypes to display_dict based on the plot backed.
+
+        The default is nothing, except for plotly based backends, where it
+        adds data for `application/vnd.plotly.v1+json` that is used in
+        frontends like jupyterlab and nteract.
+        """
+        _extra_mime_info!(plt::Plot, out::Dict) = out
+        function _extra_mime_info!(plt::Plot{PlotlyJSBackend}, out::Dict)
+            out["application/vnd.plotly.v1+json"] = JSON.lower(plt.o)
+            out
+        end
+
+        function _extra_mime_info!(plt::Plot{PlotlyBackend}, out::Dict)
+            out["application/vnd.plotly.v1+json"] = Dict(
+                :data => plotly_series(plt),
+                :layout => plotly_layout(plt)
+            )
+            out
+        end
+
         function IJulia.display_dict(plt::Plot)
             output_type = Symbol(plt.attr[:html_output_format])
             if output_type == :auto
                 output_type = get(_best_html_output_type, backend_name(plt.backend), :svg)
             end
+            out = Dict()
             if output_type == :png
                 mime = "image/png"
-                Dict{String,String}(mime => base64encode(show, MIME(mime), plt))
+                out[mime] = base64encode(show, MIME(mime), plt)
             elseif output_type == :svg
                 mime = "image/svg+xml"
-                Dict{String,String}(mime => sprint(show, MIME(mime), plt))
+                out[mime] = sprint(show, MIME(mime), plt)
             elseif output_type == :html
                 mime = "text/html"
-                Dict{String,String}(mime => sprint(show, MIME(mime), plt))
+                out[mime] = sprint(show, MIME(mime), plt)
             else
                 error("Unsupported output type $output_type")
             end
+            _extra_mime_info!(plt, out)
+            out
         end
 
         # default text/plain passes to html... handles Interact issues