1 files changed, 51 insertions, 2 deletions
diff --git a/uploader/route_utils.py b/uploader/route_utils.py
index 18eadda..4449475 100644
--- a/uploader/route_utils.py
+++ b/uploader/route_utils.py
@@ -1,12 +1,24 @@
 """Generic routing utilities."""
-from flask import flash, url_for, redirect, render_template, current_app as app
+import logging
+from json.decoder import JSONDecodeError
+
+from flask import (flash,
+                   request,
+                   redirect,
+                   render_template,
+                   current_app as app)
 
 from gn_libs.mysqldb import database_connection
 
+from uploader.flask_extensions import url_for
+from uploader.datautils import base64_encode_dict, base64_decode_to_dict
 from uploader.population.models import (populations_by_species,
                                         population_by_species_and_id)
 
-def generic_select_population(# pylint: disable=[too-many-arguments]
+logger = logging.getLogger(__name__)
+
+def generic_select_population(
+        # pylint: disable=[too-many-arguments, too-many-positional-arguments]
         species: dict,
         template: str,
         population_id: str,
@@ -39,3 +51,40 @@ def generic_select_population(# pylint: disable=[too-many-arguments]
         return redirect(url_for(forward_to,
                                 species_id=species["SpeciesId"],
                                 population_id=population["Id"]))
+
+
+def redirect_to_next(default: dict):
+    """Redirect to the next uri if specified, else redirect to default."""
+    assert "uri" in default, "You must provide at least the 'uri' value."
+    try:
+        next_page = base64_decode_to_dict(request.args.get("next"))
+        _uri = next_page["uri"]
+        next_page.pop("uri")
+        return redirect(url_for(_uri, **next_page))
+    except (TypeError, JSONDecodeError) as _err:
+        logger.debug("We could not decode the next value '%s'",
+                     next_page,
+                     exc_info=True)
+
+    return redirect(url_for(
+        default["uri"],
+        **{key:value for key,value in default.items() if key != "uri"}))
+
+
+def build_next_argument(uri: str, **kwargs) -> str:
+    """Build the `next` URI argument from provided details."""
+    dumps_keywords = (
+        "skipkeys", "ensure_ascii", "check_circular", "allow_nan", "cls",
+        "indent", "separators", "default", "sort_keys")
+    return base64_encode_dict(
+        {
+            "uri": uri,
+            **{
+                key: val for key,val in kwargs.items()
+                if key not in dumps_keywords
+            }
+        },
+        **{
+            key: val for key,val in kwargs.items()
+            if key in dumps_keywords
+        })