Intergrate the heatmap generation with the API

Issue:
https://github.com/genenetwork/gn-gemtext-threads/blob/main/topics/gn1-migration-to-gn2/clustering.gmi

* Intergrate the heatmap generation code on the /api/heatmaps/clustered
  endpoint.

  The endpoint should take a json query of the form:

      {"traits_names": [ ... ] }

  where the "traits_name" value is a list of the full names of traits.

  A sample query to the endpoint could be something like the following:

      curl -i -X POST "http://localhost:8080/api/heatmaps/clustered" \
           -H "Accept: application/json" \
           -H "Content-Type: application/json" \
           -d '{
          "traits_names": [
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM103710672",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM2260338",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM3140576",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM5670577",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM2070121",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM103990541",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM1190722",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM6590722",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM4200064",
      	    "UCLA_BXDBXH_CARTILAGE_V2::ILM3140463"
          ]
      }'

  which should respond with a json response containing the raw binary string
  for the png format and possibly another for the svg format.

1 files changed, 28 insertions, 0 deletions

diff --git a/gn3/api/heatmaps.py b/gn3/api/heatmaps.py
new file mode 100644
index 0000000..cac9c71
--- /dev/null
+++ b/gn3/api/heatmaps.py
@@ -0,0 +1,28 @@
+from flask import jsonify
+from flask import request
+from flask import Blueprint
+from gn3.heatmaps import build_heatmap
+from gn3.db_utils import database_connector
+
+heatmaps = Blueprint("heatmaps", __name__)
+
+@heatmaps.route("/clustered", methods=("POST",))
+def clustered_heatmaps():
+    heatmap_request = request.get_json()
+    traits_names = heatmap_request.get("traits_names", tuple())
+    if len(traits_names) < 1:
+        return jsonify({
+            "message": "You need to provide at least one trait name."
+        }), 400
+    conn, _cursor = database_connector()
+    _heatmap_file, heatmap_fig = build_heatmap(traits_names, conn)
+
+    # stream the heatmap data somehow here.
+    # Can plotly actually stream the figure data in a way that can be used on
+    # remote end to display the image without necessarily being html?
+    return jsonify(
+        {
+            "query": heatmap_request,
+            "output_png": heatmap_fig.to_image(format="png"),
+            "output_svg": heatmap_fig.to_image(format="svg")
+        }), 200