Merge branch 'http' into 'master'

Non-Volley HTTP Requests See merge request 415-cradle/cradlemobile!49
Cradle-VSA · Aug 16, 2020 · c3da28c · c3da28c
2 parents c4f3cde + 76260a2
commit c3da28c
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diff --git a/app/src/main/java/com/cradle/neptune/net/Http.kt b/app/src/main/java/com/cradle/neptune/net/Http.kt
@@ -0,0 +1,110 @@
+package com.cradle.neptune.net
+
+import com.cradle.neptune.model.Marshal
+import java.lang.Exception
+import java.net.HttpURLConnection
+import java.net.URL
+
+/**
+ * Contains functions for making generic HTTP requests.
+ */
+object Http {
+
+    /**
+     * Enumeration of common HTTP method request types.
+     */
+    enum class Method { GET, POST, PUT, DELETE }
+
+    /**
+     * Performs a generic HTTP request.
+     *
+     * @param method the request method
+     * @param url where to send the request
+     * @param headers HTTP headers to include with the request
+     * @param body an optional body to send along with the request
+     * @return the result of the network request
+     * @throws java.net.MalformedURLException if [url] is malformed
+     */
+    fun request(
+        method: Method,
+        url: String,
+        headers: Map<String, String>,
+        body: ByteArray?
+    ): NetworkResult<ByteArray> =
+        with(URL(url).openConnection() as HttpURLConnection) {
+            requestMethod = method.toString()
+            headers.forEach { (k, v) -> addRequestProperty(k, v) }
+            doInput = true
+
+            try {
+                if (body != null) {
+                    doOutput = true
+                    outputStream.write(body)
+                }
+
+                @Suppress("MagicNumber")
+                if (responseCode in 200 until 300) {
+                    val responseBody = inputStream.readBytes()
+                    inputStream.close()
+                    Success(responseBody, responseCode)
+                } else {
+                    val responseBody = errorStream.readBytes()
+                    errorStream.close()
+                    Failure(responseBody, responseCode)
+                }
+            } catch (ex: Exception) {
+                NetworkException(ex)
+            }
+        }
+
+    /**
+     * Sends a generic HTTP request with a JSON body and expects a JSON
+     * response.
+     *
+     * The "Content-Type application/json" header is automatically included
+     * in requests sent using this function.
+     *
+     * @param method the request method
+     * @param url where to send the request
+     * @param headers HTTP headers to include with the request
+     * @param body an optional body to send along with the request
+     * @return the result of the network request
+     * @throws java.net.MalformedURLException if [url] is malformed
+     * @throws org.json.JSONException if the response body is not JSON
+     */
+    fun jsonRequest(
+        method: Method,
+        url: String,
+        headers: Map<String, String>,
+        body: Json?
+    ): NetworkResult<Json> =
+        request(
+            method,
+            url,
+            headers + ("Content-Type" to "application/json"),
+            body?.marshal()
+        ).map(Json.Companion::unmarshal)
+
+    /**
+     * A generalized version of [jsonRequest] which accepts a generic instance
+     * for the [body] parameter.
+     *
+     * Useful for POST requests where you don't care about the response body.
+     *
+     * @param method the request method
+     * @param url where to send the request
+     * @param headers HTTP headers to include with the request
+     * @param body an optional body to send along with the request
+     * @return the result of the network request
+     * @throws java.net.MalformedURLException if [url] is malformed
+     * @throws org.json.JSONException if the response body is not JSON
+     */
+    fun <Body> jsonRequest(
+        method: Method,
+        url: String,
+        headers: Map<String, String>,
+        body: Body?
+    ): NetworkResult<Json>
+        where Body : Marshal<Json> =
+        jsonRequest(method, url, headers, body?.marshal())
+}
diff --git a/app/src/main/java/com/cradle/neptune/net/Json.kt b/app/src/main/java/com/cradle/neptune/net/Json.kt
@@ -0,0 +1,110 @@
+package com.cradle.neptune.net
+
+import com.cradle.neptune.model.Marshal
+import com.cradle.neptune.model.Unmarshal
+import org.json.JSONArray
+import org.json.JSONObject
+
+/**
+ * Sum type which represents a blob of JSON data.
+ */
+sealed class Json : Marshal<ByteArray> {
+
+    /**
+     * Unwraps this JSON data as an object.
+     *
+     * Returns `null` if this is a [JsonArray] and not a [JsonObject].
+     */
+    val obj: JSONObject?
+        get() = when (this) {
+            is JsonObject -> value
+            is JsonArray -> null
+        }
+
+    /**
+     * Unwraps this JSON data as an array.
+     *
+     * Returns `null` if this is a [JsonObject] and not a [JsonArray]
+     */
+    val arr: JSONArray?
+        get() = when (this) {
+            is JsonObject -> null
+            is JsonArray -> value
+        }
+
+    /**
+     * Converts this JSON data into a string without any line breaks or
+     * indentations.
+     *
+     * @return a string representation of the JSON data
+     */
+    abstract override fun toString(): String
+
+    /**
+     * Converts this JSON data into a string.
+     *
+     * @param indentFactor the number of spaces to used when indenting nested
+     *  structures
+     * @return a string representation of the JSON data
+     */
+    abstract fun toString(indentFactor: Int): String
+
+    /**
+     * Converts this JSON data into a byte array.
+     *
+     * @return the JSON data as a byte array
+     */
+    final override fun marshal() = toString().toByteArray()
+
+    companion object : Unmarshal<Json, ByteArray> {
+        /**
+         * Converts a byte array into a [JsonObject] or [JsonArray].
+         *
+         * @param data the byte array to parse
+         * @return a [Json] variant
+         * @throws org.json.JSONException if unable to parse [data]
+         */
+        override fun unmarshal(data: ByteArray): Json {
+            val str = String(data).trimStart()
+            return if (str.firstOrNull() == '{') {
+                JsonObject(str)
+            } else {
+                JsonArray(str)
+            }
+        }
+    }
+}
+
+/**
+ * Wraps a [JSONObject] in a [Json] variant allowing polymorphism between the
+ * two JSON types.
+ *
+ * @property value Underlying [JSONObject] value
+ */
+class JsonObject(val value: JSONObject) : Json() {
+
+    constructor() : this(JSONObject())
+
+    constructor(string: String) : this(JSONObject(string))
+
+    override fun toString() = value.toString()
+
+    override fun toString(indentFactor: Int): String = value.toString(indentFactor)
+}
+
+/**
+ * Wraps a [JSONArray] in a [Json] variant allowing polymorphism between the
+ * two JSON types.
+ *
+ * @property value Underlying [JSONArray] value
+ */
+class JsonArray(val value: JSONArray) : Json() {
+
+    constructor() : this(JSONArray())
+
+    constructor(string: String) : this(JSONArray(string))
+
+    override fun toString() = value.toString()
+
+    override fun toString(indentFactor: Int): String = value.toString(indentFactor)
+}
diff --git a/app/src/main/java/com/cradle/neptune/net/NetworkResult.kt b/app/src/main/java/com/cradle/neptune/net/NetworkResult.kt
@@ -0,0 +1,110 @@
+package com.cradle.neptune.net
+
+import com.cradle.neptune.model.Unmarshal
+
+/**
+ * Sum type representing the result of a network request.
+ */
+sealed class NetworkResult<T> {
+    /**
+     * Unwraps this network result into an optional value.
+     *
+     * @return the result value or null depending on whether the result is a
+     *  [Success], [Failure], [NetworkException] variant
+     */
+    val unwrapped: T?
+        get() = when (this) {
+            is Success -> value
+            is Failure -> null
+            is NetworkException -> null
+        }
+
+    /**
+     * Applies a closure [f] to transform the value field of a [Success] result.
+     *
+     * In the case of [Failure] and [NetworkException] variants, this method
+     * does nothing.
+     *
+     * @param f transformation to apply to the result value
+     * @return a new [NetworkResult] with the transformed value
+     */
+    fun <U> map(f: (T) -> U): NetworkResult<U> = when (this) {
+        is Success -> Success(f(value), statusCode)
+        is Failure -> Failure(body, statusCode)
+        is NetworkException -> NetworkException(cause)
+    }
+}
+
+/**
+ * The result of a successful network request.
+ *
+ * A request is considered successful if the response has a status code in the
+ * 200..<300 range.
+ *
+ * @property value The result value
+ * @property statusCode Status code of the response which generated this result
+ */
+data class Success<T>(val value: T, val statusCode: Int) : NetworkResult<T>()
+
+/**
+ * The result of a network request which made it to the server but the status
+ * code of the response indicated a failure (e.g., 404, 500, etc.).
+ *
+ * Contains the response status code along with the response body as a byte
+ * array. Note that the body is not of type [T] like in [Success] since the
+ * response for a failed request may not be the same type as the response for
+ * a successful request.
+ *
+ * @property body The body of the response
+ * @property statusCode The status code of the response
+ */
+data class Failure<T>(val body: ByteArray, val statusCode: Int) : NetworkResult<T>() {
+
+    /**
+     * Converts the response body of this failure result to some other type.
+     *
+     * @param unmarshaller an object used to unmarshall the byte array body
+     *  into a different type
+     * @return a new object which was constructed from the response body
+     */
+    fun <R, U> marshal(unmarshaller: U)
+        where U : Unmarshal<R, ByteArray> =
+        unmarshaller.unmarshal(body)
+
+    /**
+     * Converts the response body of this failure result to JSON.
+     *
+     * Whether a [JsonObject] or [JsonArray] is returned depends on the content
+     * of the response body.
+     *
+     * @return a [Json] object
+     * @throws org.json.JSONException if the response body cannot be converted
+     *  into JSON.
+     */
+    fun toJson() = marshal(Json.Companion)
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as Failure<*>
+
+        if (!body.contentEquals(other.body)) return false
+        if (statusCode != other.statusCode) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = body.contentHashCode()
+        result = 31 * result + statusCode
+        return result
+    }
+}
+
+/**
+ * Represents an exception that occurred whilst making a network request.
+ *
+ * @property cause the exception which caused the failure
+ */
+data class NetworkException<T>(val cause: Exception) : NetworkResult<T>()
diff --git a/app/src/main/java/com/cradle/neptune/network/Api.kt b/app/src/main/java/com/cradle/neptune/network/Api.kt
@@ -44,7 +44,7 @@ class Api @Inject constructor(
      * @return the response body or an error if one occurred
      */
     suspend fun authenticate(username: String, password: String): NetworkResult<JsonObject> {
-        val obj = JsonObject(mapOf("username" to username, "password" to password))
+        val obj = JsonObject(mapOf("email" to username, "password" to password))
         return requestObject(HttpMethod.POST, urlManager.authentication, obj)
     }