From b3f97dae24a8d73535feca70b1c75cf6db4737e1 Mon Sep 17 00:00:00 2001
From: Cyrus Leung <tlleungac@connect.ust.hk>
Date: Mon, 3 Aug 2026 14:51:27 +0800
Subject: [PATCH] [Frontend] Require cache_salt to be non-empty via schema
 (#50816)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>
---
 .../openai/chat_completion/protocol.py            | 13 +------------
 vllm/entrypoints/openai/completion/protocol.py    | 13 +------------
 vllm/entrypoints/openai/responses/protocol.py     | 13 +------------
 vllm/entrypoints/pooling/base/protocol.py         | 15 ---------------
 .../scale_out/token_in_token_out/protocol.py      |  1 +
 5 files changed, 4 insertions(+), 51 deletions(-)

diff --git a/vllm/entrypoints/openai/chat_completion/protocol.py b/vllm/entrypoints/openai/chat_completion/protocol.py
index 1cdfd2f698f..fc3b8103bc1 100644
--- a/vllm/entrypoints/openai/chat_completion/protocol.py
+++ b/vllm/entrypoints/openai/chat_completion/protocol.py
@@ -452,6 +452,7 @@ class ChatCompletionRequest(OpenAIBaseModel):
 
     cache_salt: str | None = Field(
         default=None,
+        min_length=1,
         description=(
             "If specified, the prefix cache will be salted with the provided "
             "string to prevent an attacker to guess prompts in multi-user "
@@ -968,18 +969,6 @@ class ChatCompletionRequest(OpenAIBaseModel):
             )
         return data
 
-    @model_validator(mode="before")
-    @classmethod
-    def check_cache_salt_support(cls, data):
-        if data.get("cache_salt") is not None and (
-            not isinstance(data["cache_salt"], str) or not data["cache_salt"]
-        ):
-            raise VLLMValidationError(
-                "Parameter 'cache_salt' must be a non-empty string if provided.",
-                parameter="cache_salt",
-            )
-        return data
-
     @model_validator(mode="before")
     @classmethod
     def check_system_message_content_type(cls, data):
diff --git a/vllm/entrypoints/openai/completion/protocol.py b/vllm/entrypoints/openai/completion/protocol.py
index 79ad9799e18..31c35b5bcce 100644
--- a/vllm/entrypoints/openai/completion/protocol.py
+++ b/vllm/entrypoints/openai/completion/protocol.py
@@ -184,6 +184,7 @@ class CompletionRequest(OpenAIBaseModel):
 
     cache_salt: str | None = Field(
         default=None,
+        min_length=1,
         description=(
             "If specified, the prefix cache will be salted with the provided "
             "string to prevent an attacker to guess prompts in multi-user "
@@ -575,18 +576,6 @@ class CompletionRequest(OpenAIBaseModel):
 
         return data
 
-    @model_validator(mode="before")
-    @classmethod
-    def check_cache_salt_support(cls, data):
-        if data.get("cache_salt") is not None and (
-            not isinstance(data["cache_salt"], str) or not data["cache_salt"]
-        ):
-            raise VLLMValidationError(
-                "Parameter 'cache_salt' must be a non-empty string if provided.",
-                parameter="cache_salt",
-            )
-        return data
-
 
 class CompletionLogProbs(OpenAIBaseModel):
     text_offset: list[int] = Field(default_factory=list)
diff --git a/vllm/entrypoints/openai/responses/protocol.py b/vllm/entrypoints/openai/responses/protocol.py
index ad92766cb7b..c739ffe25c3 100644
--- a/vllm/entrypoints/openai/responses/protocol.py
+++ b/vllm/entrypoints/openai/responses/protocol.py
@@ -243,6 +243,7 @@ class ResponsesRequest(OpenAIBaseModel):
     )
     cache_salt: str | None = Field(
         default=None,
+        min_length=1,
         description=(
             "If specified, the prefix cache will be salted with the provided "
             "string to prevent an attacker to guess prompts in multi-user "
@@ -476,18 +477,6 @@ class ResponsesRequest(OpenAIBaseModel):
             )
         return data
 
-    @model_validator(mode="before")
-    @classmethod
-    def check_cache_salt_support(cls, data):
-        if data.get("cache_salt") is not None and (
-            not isinstance(data["cache_salt"], str) or not data["cache_salt"]
-        ):
-            raise VLLMValidationError(
-                "Parameter 'cache_salt' must be a non-empty string if provided.",
-                parameter="cache_salt",
-            )
-        return data
-
     @model_validator(mode="before")
     @classmethod
     def input_item_parsing(cls, data):
diff --git a/vllm/entrypoints/pooling/base/protocol.py b/vllm/entrypoints/pooling/base/protocol.py
index c0fff022d26..fcc7c24b28c 100644
--- a/vllm/entrypoints/pooling/base/protocol.py
+++ b/vllm/entrypoints/pooling/base/protocol.py
@@ -82,21 +82,6 @@ class PoolingBasicRequestMixin(OpenAIBaseModel):
     )
     # --8<-- [end:pooling-common-extra-params]
 
-    @model_validator(mode="before")
-    @classmethod
-    def check_cache_salt_support(cls, data):
-        if not isinstance(data, dict):
-            return data
-
-        if data.get("cache_salt") is not None and (
-            not isinstance(data["cache_salt"], str) or not data["cache_salt"]
-        ):
-            raise VLLMValidationError(
-                "Parameter 'cache_salt' must be a non-empty string if provided.",
-                parameter="cache_salt",
-            )
-        return data
-
     def _build_pooling_tok_params(
         self,
         model_config: ModelConfig,
diff --git a/vllm/entrypoints/scale_out/token_in_token_out/protocol.py b/vllm/entrypoints/scale_out/token_in_token_out/protocol.py
index 8dad837613d..86c0a8c8b17 100644
--- a/vllm/entrypoints/scale_out/token_in_token_out/protocol.py
+++ b/vllm/entrypoints/scale_out/token_in_token_out/protocol.py
@@ -113,6 +113,7 @@ class GenerateRequest(BaseModel):
     stream_options: StreamOptions | None = None
     cache_salt: str | None = Field(
         default=None,
+        min_length=1,
         description=(
             "If specified, the prefix cache will be salted with the provided "
             "string to prevent an attacker to guess prompts in multi-user "