FIX URI path handling to remove double slashes

Fix request URI to remove double slashes.
Vault server returns 301 redirect for double slash URIs, requiring resending.
Since Vault server v1.17.3, the redirect URL has changed.

For example, take key: `/cubbyhole/my-secret`:

- Before vault v1.17.2, vault-ruby sends `/v1//cubbyhole/my%2Dsecret`,
  and the Vault server returns `/v1/cubbyhole/my-secret`.
- After vault v1.17.3, vault-ruby sends `/v1//cubbyhole/my%2Dsecret`,
  and the Vault server returns `/v1/cubbyhole/my%252Dsecret`.

Thus, the behavior is not the same. Removing the double slashes prevents the
redirect mechanism from being triggered.

lib/vault/client.rb

@@ -305,6 +305,15 @@ def request(verb, path, data = {}, headers = {})
       end
     end
 
+    # Removes double slashes from a path.
+    # 
+    # @param [String]
+    # 
+    # @return [String]
+    def remove_double_slash(path)
+      path.b.gsub(%r{//+}, '/')
+    end
+
     # Construct a URL from the given verb and path. If the request is a GET or
     # DELETE request, the params are assumed to be query params are are
     # converted as such using {Client#to_query_string}.
@@ -333,6 +342,8 @@ def build_uri(verb, path, params = {})
       # Don't merge absolute URLs
       uri = URI.parse(File.join(address, path)) unless uri.absolute?
 
+      uri.path = remove_double_slash(uri.path)
+
       # Return the URI object
       uri
     end

spec/integration/api/logical_spec.rb

@@ -58,6 +58,20 @@ module Vault
         expect(secret).to be
         expect(secret.data).to eq(foo: "bar")
       end
+
+      it "allows double slash" do
+        subject.write("secret/test-read", foo: "bar")
+        secret = subject.read("secret///test-read")
+        expect(secret).to be
+        expect(secret.data).to eq(foo: "bar")
+      end
+
+      it "allows double slash and special characters" do
+        subject.write("secret/b:@c%n-read-slash", foo: "bar")
+        secret = subject.read("secret///b:@c%n-read-slash")
+        expect(secret).to be
+        expect(secret.data).to eq(foo: "bar")
+      end
     end
 
     describe "#write" do
@@ -84,6 +98,21 @@ module Vault
         expect(secret.data).to eq(bacon: true)
       end
 
+      it "allows double slash" do
+        subject.write("secret///test-write", zip: "zap")
+        result = subject.read("secret/test-write")
+        expect(result).to be
+        expect(result.data).to eq(zip: "zap")
+      end
+
+      it "allows double slash and special characters" do
+        subject.write("secret///b:@c%n-write", foo: "bar")
+        subject.write("secret///b:@c%n-write", bacon: true)
+        secret = subject.read("secret/b:@c%n-write")
+        expect(secret).to be
+        expect(secret.data).to eq(bacon: true)
+      end
+
       it "respects spaces properly" do
         key = 'secret/sub/"Test Group"'
         subject.write(key, foo: "bar")
@@ -107,6 +136,18 @@ module Vault
         expect(subject.read("secret/b:@c%n-delete")).to be(nil)
       end
 
+      it "allows double slash" do
+        subject.write("secret/delete", foo: "bar")
+        expect(subject.delete("secret///delete")).to be(true)
+        expect(subject.read("secret/delete")).to be(nil)
+      end
+
+      it "allows double slash and special characters" do
+        subject.write("secret/b:@c%n-delete-slash", foo: "bar")
+        expect(subject.delete("secret///b:@c%n-delete-slash")).to be(true)
+        expect(subject.read("secret/b:@c%n-delete-slash")).to be(nil)
+      end
+
       it "does not error if the secret does not exist" do
         expect {
           subject.delete("secret/delete")