feat: cached downloads & request builder

lambda-client · emyfops · Aug 19, 2024 · Mar 24, 2024 · Mar 24, 2024 · Mar 24, 2024
commit fda87bb45d69d1258eadc3e1e0a82c59709626f2
diff --git a/common/src/main/kotlin/com/lambda/http/Method.kt b/common/src/main/kotlin/com/lambda/http/Method.kt
@@ -2,16 +2,14 @@ package com.lambda.http
 
 /**
  * Enum representing HTTP methods.
- *
- * @property value The string representation of the HTTP method.
  */
-enum class Method(val value: String) {
-    GET("GET"),
-    HEAD("HEAD"),
-    POST("POST"),
-    PUT("PUT"),
-    DELETE("DELETE"),
-    OPTIONS("OPTIONS"),
-    TRACE("TRACE"),
-    PATCH("PATCH")
+enum class Method {
+    GET,
+    HEAD,
+    POST,
+    PUT,
+    DELETE,
+    OPTIONS,
+    TRACE,
+    PATCH;
 }
diff --git a/common/src/main/kotlin/com/lambda/http/Request.kt b/common/src/main/kotlin/com/lambda/http/Request.kt
@@ -1,20 +1,24 @@
 package com.lambda.http
 
 import com.lambda.Lambda
-import com.lambda.Lambda.LOG
+import com.lambda.util.FolderRegister.cache
+import java.io.File
 import java.net.HttpURLConnection
 import java.net.URL
+import java.time.Instant
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.days
 
 /**
- * Represents an HTTP request handler that allows making various HTTP requests.
+ * Represents an HTTP request.
  *
  * @property url The URL to which the request will be made.
  * @property method The HTTP method to be used for the request. Default is [Method.GET].
  * @property parameters A map of query parameters to be included in the request. Default is an empty map.
  * @property headers A map of headers to be included in the request. Default is an empty map.
  * @property config A lambda function to configure the HTTP connection. Default is an empty lambda.
  */
-class Request(
+data class Request(
     val url: String,
     val method: Method = Method.GET,
     val parameters: Map<String, Any> = mapOf(),
@@ -26,6 +30,43 @@ class Request(
     val canBeEncoded: Boolean
         get() = method != Method.POST && method != Method.PUT && method != Method.PATCH
 
+    /**
+     * Downloads the resource at the specified path and caches it for future use.
+     *
+     * @param path The path to the resource.
+     * @param maxAge The maximum age of the cached resource. Default is 4 days.
+     */
+    fun maybeDownload(path: String, maxAge: Duration = 4.days): ByteArray {
+        val file = File("${cache}/${path.substringAfterLast("/").hashCode()}")
+
+        if (file.exists() && Instant.now().toEpochMilli() - file.lastModified() < maxAge.inWholeMilliseconds)
+            return file.readBytes()
+
+        file.writeText("") // Clear the file before writing to it.
+
+        val url = URL(
+            if (parameters.isNotEmpty() && canBeEncoded) "$url?${parameters.query}"
+            else url
+        )
+
+        val connection = url.openConnection() as HttpURLConnection
+        config.invoke(connection)
+
+        connection.requestMethod = method.name
+
+        headers.forEach { (key, value) -> connection.setRequestProperty(key, value) }
+
+        connection.connect()
+
+        connection.inputStream.use { input ->
+            file.outputStream().use { output ->
+                input.copyTo(output)
+            }
+        }
+
+        return file.readBytes()
+    }
+
     /**
      * Executes the HTTP request synchronously.
      */
@@ -38,7 +79,7 @@ class Request(
         val connection = url.openConnection() as HttpURLConnection
         config.invoke(connection)
 
-        connection.requestMethod = method.value
+        connection.requestMethod = method.name
 
         headers.forEach { (key, value) -> connection.setRequestProperty(key, Lambda.gson.toJson(value)) }
 

diff --git a/common/src/main/kotlin/com/lambda/http/RequestBuilder.kt b/common/src/main/kotlin/com/lambda/http/RequestBuilder.kt
@@ -0,0 +1,59 @@
+package com.lambda.http
+
+import java.net.HttpURLConnection
+
+@Target(AnnotationTarget.CLASS, AnnotationTarget.TYPE)
+@DslMarker
+annotation class RequestDsl
+
+@RequestDsl
+class RequestBuilder(
+    private val url: String,
+) {
+    private var method: Method = Method.GET
+    private val parameters: MutableMap<String, Any> = mutableMapOf()
+    private val headers: MutableMap<String, String> = mutableMapOf()
+    private var config: ((HttpURLConnection) -> Unit) = {}
+
+    /**
+     * Sets the HTTP method to be used for the request.
+     */
+    fun method(method: Method): RequestBuilder {
+        this.method = method
+        return this
+    }
+
+    /**
+     * Sets the query parameters to be included in the request.
+     */
+    fun parameters(parameters: Map<String, Any>): RequestBuilder {
+        this.parameters.putAll(parameters)
+        return this
+    }
+
+    /**
+     * Sets the headers to be included in the request.
+     */
+    fun headers(headers: Map<String, String>): RequestBuilder {
+        this.headers.putAll(headers)
+        return this
+    }
+
+    /**
+     * Sets the lambda function to configure the HTTP connection.
+     */
+    fun config(config: (HttpURLConnection) -> Unit): RequestBuilder {
+        this.config = config
+        return this
+    }
+
+    fun build() = Request(url, method, parameters, headers, config)
+}
+
+/**
+ * Creates an HTTP request.
+ *
+ * @param url The URL to which the request will be made.
+ * @param block A lambda function to configure the request.
+ */
+inline fun request(url: String, block: (@RequestDsl RequestBuilder).() -> Unit) = RequestBuilder(url).apply(block).build()
diff --git a/common/src/main/kotlin/com/lambda/util/FolderRegister.kt b/common/src/main/kotlin/com/lambda/util/FolderRegister.kt
@@ -28,6 +28,7 @@ object FolderRegister {
     val config: File = File(lambda, "config")
     val packetLogs: File = File(lambda, "packet-log")
     val replay: File = File(lambda, "replay")
+    val cache: File = File(lambda, "cache")
 
     fun File.createIfNotExists() {
         if (!exists()) {