add API key + endpoint validation

Author: esoteric-ephemera

mp_api/client/core/settings.py

@@ -2,7 +2,7 @@
 from multiprocessing import cpu_count
 from typing import List
 
-from pydantic import Field
+from pydantic import Field, field_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 from pymatgen.core import _load_pmg_settings
 
@@ -14,6 +14,7 @@
 _MUTE_PROGRESS_BAR = PMG_SETTINGS.get("MPRESTER_MUTE_PROGRESS_BARS", False)
 _MAX_HTTP_URL_LENGTH = PMG_SETTINGS.get("MPRESTER_MAX_HTTP_URL_LENGTH", 2000)
 _MAX_LIST_LENGTH = min(PMG_SETTINGS.get("MPRESTER_MAX_LIST_LENGTH", 10000), 10000)
+_DEFAULT_ENDPOINT = "https://api.materialsproject.org/"
 
 try:
     CPU_COUNT = cpu_count()
@@ -80,11 +81,21 @@ class MAPIClientSettings(BaseSettings):
     )
 
     MIN_EMMET_VERSION: str = Field(
-        "0.54.0", description="Minimum compatible version of emmet-core for the client."
+        "0.86.3rc0",
+        description="Minimum compatible version of emmet-core for the client.",
     )
 
     MAX_LIST_LENGTH: int = Field(
         _MAX_LIST_LENGTH, description="Maximum length of query parameter list"
     )
 
+    ENDPOINT: str = Field(
+        _DEFAULT_ENDPOINT, description="The default API endpoint to use."
+    )
+
     model_config = SettingsConfigDict(env_prefix="MPRESTER_")
+
+    @field_validator("ENDPOINT", mode="before")
+    def _get_endpoint_from_env(cls, v: str | None) -> str:
+        """Support setting endpoint via MP_API_ENDPOINT environment variable."""
+        return v or os.environ.get("MP_API_ENDPOINT") or _DEFAULT_ENDPOINT

mp_api/client/core/utils.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import os
 from typing import TYPE_CHECKING, Literal
 
 import orjson
@@ -50,6 +51,25 @@ def load_json(
     return MontyDecoder().process_decoded(data) if deser else data
 
 
+def validate_api_key(api_key: str | None = None) -> str:
+    """Find and validate an API key."""
+    # SETTINGS tries to read API key from ~/.config/.pmgrc.yaml
+    api_key = api_key or os.getenv("MP_API_KEY")
+    if not api_key:
+        from pymatgen.core import SETTINGS
+
+        api_key = SETTINGS.get("PMG_MAPI_KEY")
+
+    if not api_key or len(api_key) != 32:
+        addendum = " Valid API keys are 32 characters." if api_key else ""
+        raise ValueError(
+            "Please obtain a valid API key from https://materialsproject.org/api "
+            f"and export it as an environment variable `MP_API_KEY`.{addendum}"
+        )
+
+    return api_key
+
+
 def validate_ids(id_list: list[str]) -> list[str]:
     """Function to validate material and task IDs.
 

mp_api/client/mprester.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import itertools
-import os
 import warnings
 from collections import defaultdict
 from functools import cache, lru_cache
@@ -16,7 +15,7 @@
 from packaging import version
 from pymatgen.analysis.phase_diagram import PhaseDiagram
 from pymatgen.analysis.pourbaix_diagram import IonEntry
-from pymatgen.core import SETTINGS, Composition, Element, Structure
+from pymatgen.core import Composition, Element, Structure
 from pymatgen.core.ion import Ion
 from pymatgen.entries.computed_entries import ComputedStructureEntry
 from pymatgen.io.vasp import Chgcar
@@ -26,7 +25,7 @@
 from mp_api.client.core import BaseRester, MPRestError
 from mp_api.client.core._oxygen_evolution import OxygenEvolution
 from mp_api.client.core.settings import MAPIClientSettings
-from mp_api.client.core.utils import load_json, validate_ids
+from mp_api.client.core.utils import load_json, validate_api_key, validate_ids
 from mp_api.client.routes import GeneralStoreRester, MessagesRester, UserSettingsRester
 from mp_api.client.routes.materials import (
     AbsorptionRester,
@@ -165,20 +164,12 @@ def __init__(
             mute_progress_bars:  Whether to mute progress bars.
             **kwargs: access to legacy kwargs that may be in the process of being deprecated
         """
-        # SETTINGS tries to read API key from ~/.config/.pmgrc.yaml
-        api_key = api_key or os.getenv("MP_API_KEY") or SETTINGS.get("PMG_MAPI_KEY")
+        self.api_key = validate_api_key(api_key)
 
-        if api_key and len(api_key) != 32:
-            raise ValueError(
-                "Please use a new API key from https://materialsproject.org/api "
-                "Keys for the new API are 32 characters, whereas keys for the legacy "
-                "API are 16 characters."
-            )
+        self.endpoint = endpoint or _MAPI_SETTINGS.ENDPOINT
+        if not self.endpoint.endswith("/"):
+            self.endpoint += "/"
 
-        self.api_key = api_key
-        self.endpoint = endpoint or os.getenv(
-            "MP_API_ENDPOINT", "https://api.materialsproject.org/"
-        )
         self.headers = headers or {}
         self.session = session or BaseRester._create_session(
             api_key=self.api_key,
@@ -219,9 +210,6 @@ def __init__(
             "chemenv",
         ]
 
-        if not self.endpoint.endswith("/"):
-            self.endpoint += "/"
-
         if "monty_decode" in kwargs:
             warnings.warn(
                 "Ignoring `monty_decode`, as it is no longer a supported option in `mp_api`."

tests/core/test_utils.py

@@ -46,3 +46,39 @@ def test_id_validation():
         isinstance(x, str) and AlphaID(x).string == x
         for x in validate_ids([y + AlphaID._cut_point for y in range(max_num_idxs)])
     )
+
+
+def test_api_key_validation(monkeypatch: pytest.MonkeyPatch):
+    from mp_api.client.core.utils import validate_api_key
+    import pymatgen.core
+
+    # Ensure any user settings are ignored
+    monkeypatch.setenv("MP_API_KEY", "")
+    monkeypatch.setenv("PMG_MAPI_KEY", "")
+    non_api_key_settings = {
+        k: v for k, v in pymatgen.core.SETTINGS.items() if k != "PMG_MAPI_KEY"
+    }
+    monkeypatch.setattr(pymatgen.core, "SETTINGS", non_api_key_settings)
+
+    with pytest.raises(ValueError, match="32 characters"):
+        validate_api_key("invalid_key")
+
+    with pytest.raises(ValueError, match="Please obtain a valid"):
+        validate_api_key()
+
+    junk_api_key = "a" * 32
+    monkeypatch.setenv("MP_API_KEY", junk_api_key)
+    assert validate_api_key() == junk_api_key
+    assert validate_api_key(junk_api_key) == junk_api_key
+
+    other_junk_api_key = "b" * 32
+    monkeypatch.setattr(
+        pymatgen.core,
+        "SETTINGS",
+        {**non_api_key_settings, "PMG_MAPI_KEY": other_junk_api_key},
+    )
+    # MP API environment variable takes precedence
+    assert validate_api_key() == junk_api_key
+
+    monkeypatch.setenv("MP_API_KEY", "")
+    assert validate_api_key() == other_junk_api_key