better support for relative constraints

.pre-commit-config.yaml

@@ -66,7 +66,7 @@ repos:
         - --quiet-level=2
 
 - repo: https://github.com/asottile/pyupgrade
-  rev: v2.26.0
+  rev: v2.28.0
   hooks:
     - id: pyupgrade
       args:

erddapy/erddapy.py

@@ -28,10 +28,13 @@
 def _quote_string_constraints(kwargs: Dict) -> Dict:
     """
     For constraints of String variables,
-    the right-hand-side value must be surrounded by double quotes.
+    the right-hand-side value must be surrounded by double quotes if they are not relative constraints.
 
     """
-    return {k: f'"{v}"' if isinstance(v, str) else v for k, v in kwargs.items()}
+    return {
+        k: f'"{v}"' if isinstance(v, str) and not _check_substrings(v) else v
+        for k, v in kwargs.items()
+    }
 
 
 def _format_constraints_url(kwargs: Dict) -> str:
@@ -42,6 +45,16 @@ def _format_constraints_url(kwargs: Dict) -> str:
     return "".join([f"&{k}{v}" for k, v in kwargs.items()])
 
 
+def _check_substrings(constraint):
+    """
+    The tabledap protocol extends the OPeNDAP with these strings and we
+    need to pass them intact to the URL builder.
+
+    """
+    substrings = ["now", "min", "max"]
+    return any([True for substring in substrings if substring in str(constraint)])
+
+
 def parse_dates(date_time: Union[datetime, str]) -> float:
     """
     ERDDAP ReSTful API standardizes the representation of dates as either ISO
@@ -147,7 +160,6 @@ class ERDDAP:
         variables: a list variables to download.
         response: default is HTML.
         constraints: download constraints, default None (opendap-like url)
-        relative_constraints: download constraints based on ERDDAP server calculations, default None
         params and requests_kwargs: `request.get` options
 
     Returns:
@@ -211,7 +223,6 @@ def __init__(
 
         # Initialized only via properties.
         self.constraints: Optional[Dict] = None
-        self.relative_constraints: Optional[Dict] = None
         self.server_functions: Optional[Dict] = None
         self.dataset_id: OptionalStr = None
         self.requests_kwargs: Dict = {}
@@ -317,12 +328,16 @@ def get_search_url(
             base += "&searchFor={searchFor}"
 
         # Convert dates from datetime to `seconds since 1970-01-01T00:00:00Z`.
-        min_time = kwargs.pop("min_time", None)
-        max_time = kwargs.pop("max_time", None)
-        if min_time:
+        min_time = kwargs.pop("min_time", "")
+        max_time = kwargs.pop("max_time", "")
+        if min_time and not _check_substrings(min_time):
             kwargs.update({"min_time": parse_dates(min_time)})
-        if max_time:
+        else:
+            kwargs.update({"min_time": min_time})
+        if max_time and not _check_substrings(max_time):
             kwargs.update({"max_time": parse_dates(max_time)})
+        else:
+            kwargs.update({"max_time": max_time})
 
         protocol = protocol if protocol else self.protocol
         response = response if response else self.response
@@ -427,7 +442,6 @@ def get_download_url(
         dim_names: Optional[ListLike] = None,
         response=None,
         constraints=None,
-        relative_constraints=None,
         **kwargs,
     ) -> str:
         """The download URL for the `server` endpoint.
@@ -445,11 +459,9 @@ def get_download_url(
                                     'time<=': '2017-02-10T00:00:00+00:00',
                                     'time>=': '2016-07-10T00:00:00+00:00',}
 
-            relative_constraints (dict): advanced download constraints , default None
-            example: relative_constraints = {'time>': 'now-7days',
-                                         'latitude<':'min(longitude)+180'
-                                         'depth>':'max(depth)-23'
-                                            }
+            One can also use relative constraints like {'time>': 'now-7days',
+                                                        'latitude<': 'min(longitude)+180',
+                                                        'depth>': 'max(depth)-23',}
 
         Returns:
             url (str): the download URL for the `response` chosen.
@@ -461,9 +473,6 @@ def get_download_url(
         dim_names = dim_names if dim_names else self.dim_names
         response = response if response else self.response
         constraints = constraints if constraints else self.constraints
-        relative_constraints = (
-            relative_constraints if relative_constraints else self.relative_constraints
-        )
 
         if not dataset_id:
             raise ValueError(f"Please specify a valid `dataset_id`, got {dataset_id}")
@@ -517,17 +526,15 @@ def get_download_url(
         if constraints:
             _constraints = copy.copy(constraints)
             for k, v in _constraints.items():
+                if _check_substrings(v):
+                    continue
                 if k.startswith("time"):
                     _constraints.update({k: parse_dates(v)})
             _constraints = _quote_string_constraints(_constraints)
             _constraints_url = _format_constraints_url(_constraints)
 
             url += f"{_constraints_url}"
 
-        if relative_constraints:
-            _relative_constraints_url = _format_constraints_url(relative_constraints)
-            url += f"{_relative_constraints_url}"
-
         url = _distinct(url, **kwargs)
         return url
 

notebooks/00-quick_intro.ipynb

@@ -25,7 +25,7 @@
    "source": [
     "First we need to instantiate the ERDDAP URL constructor for a server. In this\n",
     "example we will use\n",
-    "[https://gliders.ioos.us/erddap](https://gliders.ioos.us/erddap/index.html).\n"
+    "[https://upwell.pfeg.noaa.gov/erddap](https://upwell.pfeg.noaa.gov/erddap/index.html).\n"
    ]
   },
   {
@@ -38,7 +38,7 @@
     "\n",
     "\n",
     "e = ERDDAP(\n",
-    "    server=\"NGDAC\",  # \"NOAA IOOS NGDAC (National Glider Data Assembly Center)\"\n",
+    "    server=\"UAF\",  # NOAA UAF (Unified Access Framework)\n",
     "    protocol=\"tabledap\",\n",
     "    response=\"csv\",\n",
     ")"
@@ -49,7 +49,7 @@
    "metadata": {},
    "source": [
     "Now we can populate the object a dataset id, variables of interest, and its\n",
-    "constraints. We can download the csvp response with the `.to_pandas` method.\n"
+    "constraints (last week gliders). Use the method `to_pandas` to download the csv(p) response, a comma separated values with units and explore the Dataframe.\n"
    ]
   },
   {
@@ -58,7 +58,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "e.dataset_id = \"whoi_406-20160902T1700\"\n",
+    "e.dataset_id = \"scrippsGliders\"\n",
     "\n",
     "e.variables = [\n",
     "    \"depth\",\n",
@@ -70,12 +70,7 @@
     "]\n",
     "\n",
     "e.constraints = {\n",
-    "    \"time>=\": \"2016-09-03T00:00:00Z\",\n",
-    "    \"time<=\": \"2016-09-04T00:00:00Z\",\n",
-    "    \"latitude>=\": 38.0,\n",
-    "    \"latitude<=\": 41.0,\n",
-    "    \"longitude>=\": -72.0,\n",
-    "    \"longitude<=\": -69.0,\n",
+    "    \"time>=\": \"now-7days\",\n",
     "}\n",
     "\n",
     "\n",
@@ -86,6 +81,71 @@
     "\n",
     "df.head()"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "We can constraint the in time and space with relative constraints like in the example below. For more ways to access the data please check the \"Longer introduction.\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "constraints = {\n",
+    "    \"time>=\": \"now-14days\",\n",
+    "    \"time<=\": \"now-7days\",\n",
+    "    \"latitude>=\": \"min(latitude)+5\",\n",
+    "    \"latitude<=\": \"max(latitude)-5\",\n",
+    "    \"longitude>=\": \"min(longitude)+5\",\n",
+    "    \"longitude<=\": \"min(longitude)+10\",\n",
+    "    \"depth>=\": \"min(depth)+5\",\n",
+    "    \"depth<=\": \"max(depth)-40\",\n",
+    "}\n",
+    "\n",
+    "\n",
+    "url = e.get_download_url(\n",
+    "    response=\"html\",\n",
+    "    constraints=constraints,\n",
+    ")\n",
+    "\n",
+    "print(url)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The same request as above but with non-relative constraints. Note that these values will change if we run this at a later time."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "constraints = {\n",
+    "    \"time>=\": \"2021-09-11T23:26:55Z\",\n",
+    "    \"time<=\": \"2021-09-18T23:26:55Z\",\n",
+    "    \"latitude>=\": -7.52,\n",
+    "    \"latitude<=\": 46.67,\n",
+    "    \"longitude>=\": -121.48,\n",
+    "    \"longitude<=\": -116.48,\n",
+    "    \"depth>=\": -3.82,\n",
+    "    \"depth<=\": 1001.59,\n",
+    "}\n",
+    "\n",
+    "url = e.get_download_url(\n",
+    "    response=\"html\",\n",
+    "    constraints=constraints,\n",
+    ")\n",
+    "\n",
+    "print(url)"
+   ]
   }
  ],
  "metadata": {
@@ -101,7 +161,7 @@
   },
   "gist_id": "3f0f25b13ade0c64c84607bd92903d1b",
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -115,7 +175,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.8.5"
+   "version": "3.9.7"
   }
  },
  "nbformat": 4,

tests/cassettes/test_download_url_distinct.yaml

@@ -0,0 +1,42 @@
+interactions:
+- request:
+    body: null
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate, br
+      Connection:
+      - keep-alive
+      User-Agent:
+      - python-requests/2.26.0
+    method: HEAD
+    uri: https://upwell.pfeg.noaa.gov/erddap/tabledap/gtoppAT.htmlTable?commonName,yearDeployed,serialNumber&distinct()
+  response:
+    body:
+      string: ''
+    headers:
+      Connection:
+      - close
+      Content-Type:
+      - text/plain; charset=UTF-8
+      Date:
+      - Fri, 24 Sep 2021 23:36:03 GMT
+      Last-Modified:
+      - Fri, 24 Sep 2021 23:36:03 GMT
+      Location:
+      - https://oceanview.pfeg.noaa.gov/erddap/tabledap/gtoppAT.htmlTable?commonName%2CyearDeployed%2CserialNumber&distinct()
+      Strict-Transport-Security:
+      - max-age=31536000; includeSubDomains
+      Transfer-Encoding:
+      - chunked
+      X-Frame-Options:
+      - SAMEORIGIN
+      erddap-server:
+      - '2.02'
+      xdods-server:
+      - dods/3.7
+    status:
+      code: 302
+      message: ''
+version: 1