PortwayCaching
Successful GET responses from SQL and proxy endpoints are cached in memory or Redis. Only 2xx responses with a cacheable content type are stored.
Providers
| Provider | Use case |
|---|---|
Memory |
Single instance; cleared on restart |
Redis |
Shared across instances; kept across restarts |
Configuration
{
"Caching": {
"Enabled": true,
"DefaultCacheDurationSeconds": 300,
"ProviderType": "Memory",
"MemoryCacheSizeLimitMB": 100,
"CacheableContentTypes": [
"application/json",
"text/json"
],
"EndpointCacheDurations": {
"Products": 600,
"Customers": 300
}
}
}Property reference
| Property | Type | Default | Description |
|---|---|---|---|
Enabled |
boolean | true |
Enable response caching |
DefaultCacheDurationSeconds |
integer | 300 |
Default TTL for cached responses |
ProviderType |
string | "Memory" |
Cache backend: "Memory" or "Redis" |
MemoryCacheSizeLimitMB |
integer | 100 |
Memory budget in MB; entries are evicted once cached payloads exceed it |
CacheableContentTypes |
array | ["application/json", ...] |
Only cache responses with these content types |
EndpointCacheDurations |
object | {} |
Per-endpoint TTL overrides keyed by endpoint name |
Redis configuration
{
"Caching": {
"ProviderType": "Redis",
"Redis": {
"ConnectionString": "localhost:6379",
"InstanceName": "Portway:",
"Database": 0,
"UseSsl": false,
"ConnectTimeoutMs": 5000,
"AbortOnConnectFail": false,
"FallbackToMemoryCache": true,
"MaxRetryAttempts": 3,
"RetryDelayMs": 200
}
}
}| Property | Type | Default | Description |
|---|---|---|---|
ConnectionString |
string | "localhost:6379" |
Redis connection string |
InstanceName |
string | "Portway:" |
Key prefix for all cache entries |
Database |
integer | 0 |
Redis logical database index |
UseSsl |
boolean | false |
Use TLS for the Redis connection |
ConnectTimeoutMs |
integer | 5000 |
Connection timeout in milliseconds |
AbortOnConnectFail |
boolean | false |
Throw on connection failure instead of retrying |
FallbackToMemoryCache |
boolean | true |
Fall back to in-process memory cache if Redis is unavailable |
MaxRetryAttempts |
integer | 3 |
Retry attempts on transient Redis errors |
RetryDelayMs |
integer | 200 |
Delay between retry attempts in milliseconds |
Cache behaviour
Cached responses
GET responses from SQL and proxy endpoints with a 2xx status and a content type in CacheableContentTypes. POST, PUT, DELETE and PATCH responses and error responses are not cached.
Cache keys
Proxy keys combine the URL and query string, environment, endpoint name, a hash of the Authorization header, the selected tenant values and Accept-Language. SQL keys combine the environment, endpoint name and the generated SQL with its parameters, which include tenant predicates.
Cache invalidation
Entries expire after their TTL. A non-GET request to an endpoint invalidates its entries.
Cache durations
The TTL is DefaultCacheDurationSeconds; EndpointCacheDurations overrides it per endpoint. A response with Cache-Control: max-age=N uses that value.
High-Availability Redis
Sentinel
"Redis": {
"ConnectionString": "sentinel-master-name,sentinel1:26379,sentinel2:26379",
"InstanceName": "Portway:"
}Cluster
"Redis": {
"ConnectionString": "redis1:6379,redis2:6379,redis3:6379",
"InstanceName": "Portway:"
}With FallbackToMemoryCache: true, an unavailable Redis switches caching to memory with a logged warning; Redis is used again after the connection recovers.
Cache statistics
The detailed health check (GET /health/details) includes item count, hit and miss ratio, memory usage and Redis connection status.
Troubleshooting
Redis diagnostic commands
redis-cli ping
redis-cli info memory
redis-cli --scan --pattern "Portway:*"Common issues
| Symptom | Likely cause | Fix |
|---|---|---|
| No caching | Caching.Enabled is false, or not a GET request |
Set Enabled: true |
| Content type not cached | Not in CacheableContentTypes |
Add the content type |
| Redis connection failures | Wrong connection string or unreachable server | Verify ConnectionString; check firewall |
| High memory usage | Long TTL or a generous budget | Reduce DefaultCacheDurationSeconds or MemoryCacheSizeLimitMB |