CharmHub - Charm URL

juju/url.py

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+from enum import Enum
+from .errors import JujuError
+from urllib.parse import urlparse
+
+
+class Schema(Enum):
+    LOCAL = "local"
+    CHARM_STORE = "cs"
+    CHARM_HUB = "ch"
+
+    def matches(self, potential):
+        return self.value == potential
+
+    def __str__(self):
+        return self.value
+
+
+class URL:
+    def __init__(self, schema, user=None, name=None, revision=None, series=None):
+        self.schema = schema
+        self.user = user
+        self.name = name
+        self.series = series
+
+        # 0 can be a valid revision, hence the more verbose check.
+        if revision is None:
+            revision = -1
+        self.revision = revision
+
+    @staticmethod
+    def parse(s):
+        """parse parses the provided charm URL string into its respective
+            structure.
+
+            A missing schema is assumed to be 'ch'.
+
+        """
+        u = urlparse(s)
+        if u.query != "" or u.fragment != "" or u.username or u.password:
+            raise JujuError("charm or bundle URL {} has unrecognized parts".format(u))
+
+        if Schema.LOCAL.matches(u.scheme):
+            c = parse_v1_url(Schema.LOCAL, u, s)
+        elif Schema.CHARM_STORE.matches(u.scheme):
+            c = parse_v1_url(Schema.CHARM_STORE, u, s)
+        else:
+            c = parse_v2_url(u, s)
+
+        if not c.schema:
+            raise JujuError("expected schema for charm or bundle URL {}".format(u))
+        return c
+
+    def with_revision(self, rev):
+        return URL(self.schema, self.user, self.name, rev, self.series)
+
+    def path(self):
+        parts = []
+        if self.user:
+            parts.append("~{}".format(self.user))
+        if self.series:
+            parts.append(self.series)
+        if self.revision is not None and self.revision >= 0:
+            parts.append("{}-{}", self.name, self.revision)
+        else:
+            parts.append(self.name)
+        return "/".join(parts)
+
+    def __eq__(self, other):
+        if isinstance(other, self.__class__):
+            return self.schema == other.schema and \
+                self.user == other.user and \
+                self.name == other.name and \
+                self.revision == other.revision and \
+                self.series == other.series
+        return False
+
+    def __str__(self):
+        return "{}:{}".format(str(self.schema), self.path())
+
+
+def parse_v1_url(schema, u, s):
+    c = URL(schema)
+
+    parts = u.path.split("/")
+    if len(parts) < 1 or len(parts) > 4:
+        raise JujuError("charm or bundle URL has invalid form {}".format(s))
+
+    # ~<username>
+    if parts[0].startswith("~"):
+        if schema == Schema.LOCAL:
+            raise JujuError("local charm or bundle URL with username {}".format(s))
+        c.user = parts[0][1:]
+        parts = parts[1:]
+
+    if len(parts) > 2:
+        raise JujuError("charm or bundle URL has invalid form {}".format(s))
+
+    # <series>
+    if len(parts) == 2:
+        c.series = parts[0]
+        parts = parts[1:]
+        # TODO (stickupkid) - validate the series.
+
+    if len(parts) < 1:
+        raise JujuError("URL without charm or bundle name {}".format(s))
+
+    (c.name, c.revision) = extract_revision(parts[0])
+    # TODO (stickupkid) - validate the name.
+
+    return c
+
+
+def parse_v2_url(u, s):
+    c = URL(Schema.CHARM_HUB)
+
+    parts = u.path.split("/")
+    if len(parts) != 1:
+        raise JujuError("charm or bundle URL {} malformed, expected <name>".format(s))
+
+    (c.name, c.revision) = extract_revision(parts[0])
+    # TODO (stickupkid) - validate the name.
+
+    return c
+
+
+def extract_revision(name):
+    revision = -1
+    for i in range(len(name) - 1, -1, -1):
+        c = name[i]
+        if c.isnumeric():
+            continue
+        if c == "-" and i != (len(name) - 1):
+            revision = int(name[(i + 1):])
+            name = name[:i]
+        break
+    return (name, revision)

tests/unit/test_url.py

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+import unittest
+
+from juju.url import Schema, URL
+
+
+class TestURLV1(unittest.TestCase):
+    def test_parse_charmstore(self):
+        u = URL.parse("cs:mysql")
+        self.assertEqual(u, URL(Schema.CHARM_STORE, name="mysql"))
+
+    def test_parse_local(self):
+        u = URL.parse("local:mysql")
+        self.assertEqual(u, URL(Schema.LOCAL, name="mysql"))
+
+    def test_parse_v1_user(self):
+        u = URL.parse("cs:~fred/mysql")
+        self.assertEqual(u, URL(Schema.CHARM_STORE, name="mysql", user="fred"))
+
+    def test_parse_v1_revision(self):
+        u = URL.parse("cs:~fred/mysql-1")
+        self.assertEqual(u, URL(Schema.CHARM_STORE, name="mysql", user="fred", revision=1))
+
+    def test_parse_v1_large_revision(self):
+        u = URL.parse("cs:~fred/mysql-12345")
+        self.assertEqual(u, URL(Schema.CHARM_STORE, name="mysql", user="fred", revision=12345))
+
+    def test_parse_v1_series(self):
+        u = URL.parse("cs:~fred/bionic/mysql-1")
+        self.assertEqual(u, URL(Schema.CHARM_STORE, name="mysql", user="fred", revision=1, series="bionic"))
+
+
+class TestURLV2(unittest.TestCase):
+    def test_parse_charmhub(self):
+        u = URL.parse("ch:mysql")
+        self.assertEqual(u, URL(Schema.CHARM_HUB, name="mysql"))
+
+    def test_parse_v2_revision(self):
+        u = URL.parse("ch:mysql-1")
+        self.assertEqual(u, URL(Schema.CHARM_HUB, name="mysql", revision=1))
+
+    def test_parse_v2_large_revision(self):
+        u = URL.parse("ch:mysql-12345")
+        self.assertEqual(u, URL(Schema.CHARM_HUB, name="mysql", revision=12345))