fix #179: centralize and fix HttpResponse parsing and error handling

Before this change, only HttpException were thrown on errors. However it is possible to receive errors but formatted as OCPI messages, and in this case we want to throw an OcpiException and not an HttpException

Author: lilgallon

ocpi-toolkit-2.2.1/src/main/kotlin/com/izivia/ocpi/toolkit/common/HttpResponse.kt

@@ -41,27 +41,17 @@ inline fun <reified T, reified P : Partial<T>> HttpResponse.parseSearchResultIgn
  * information. Any error information contained in HTTP request or OCPI body gets converted into Exceptions.
  * @param offset
  */
-inline fun <reified T> HttpResponse.parseSearchResult(offset: Int): SearchResult<T> {
-    if (!status.success()) throw HttpException(status, status.name)
-    if (body.isNullOrBlank()) throw OcpiToolkitResponseParsingException("missing obligatory body in response")
-
-    val list = runCatching { mapper.deserializeOcpiResponseList<T>(body) }
-        .onFailure { e ->
-            throw OcpiToolkitResponseParsingException("Response cannot be parsed: $body", e)
-        }
-        .getOrNull()
-        ?.also { it.maybeThrowOcpiException(status) }
-        ?.data ?: emptyList()
-
-    return list.toSearchResult(
-        totalCount = getHeader(Header.X_TOTAL_COUNT)?.toInt()
-            ?: throw OcpiToolkitMissingRequiredResponseHeaderException(Header.X_TOTAL_COUNT),
-        limit = getHeader(Header.X_LIMIT)?.toInt()
-            ?: throw OcpiToolkitMissingRequiredResponseHeaderException(Header.X_LIMIT),
-        offset = offset,
-        nextPageUrl = getHeader(Header.LINK)?.split("<")?.elementAtOrNull(1)?.split(">")?.first(),
-    )
-}
+inline fun <reified T> HttpResponse.parseSearchResult(offset: Int): SearchResult<T> =
+    parseOcpiResponseBodyAndHandleErrors { mapper.deserializeOcpiResponseList<T>(body) }
+        .orEmpty()
+        .toSearchResult(
+            totalCount = getHeader(Header.X_TOTAL_COUNT)?.toInt()
+                ?: throw OcpiToolkitMissingRequiredResponseHeaderException(Header.X_TOTAL_COUNT),
+            limit = getHeader(Header.X_LIMIT)?.toInt()
+                ?: throw OcpiToolkitMissingRequiredResponseHeaderException(Header.X_LIMIT),
+            offset = offset,
+            nextPageUrl = getHeader(Header.LINK)?.split("<")?.elementAtOrNull(1)?.split(">")?.first(),
+        )
 
 /**
  * Parse body of a request that should contain data, usually POST commands.
@@ -85,43 +75,52 @@ inline fun <reified T> HttpResponse.parseOptionalResult(): T? {
     return parseResultOrNull()
 }
 
-inline fun <reified T> HttpResponse.parseResultListOrNull(): List<T>? {
-    if (!status.success()) throw HttpException(status, status.name)
-    if (body.isNullOrBlank()) throw OcpiToolkitResponseParsingException("missing obligatory body in response")
+inline fun <reified T> HttpResponse.parseResultListOrNull(): List<T>? =
+    parseOcpiResponseBodyAndHandleErrors { mapper.deserializeOcpiResponseList<T>(body) }
 
-    return runCatching { mapper.deserializeOcpiResponseList<T>(body) }
-        .onFailure { e ->
-            throw OcpiToolkitResponseParsingException("Response cannot be parsed: $body", e)
-        }
-        .getOrNull()
-        ?.also { it.maybeThrowOcpiException(status) }
-        ?.data
-}
+inline fun <reified T> HttpResponse.parseResultOrNull(): T? =
+    parseOcpiResponseBodyAndHandleErrors { mapper.deserializeOcpiResponse<T>(it) }
 
 /**
  * Parse body of a request that might contain data, like PUT/PATCH calls.
  * Any error information contained in HTTP request or OcpiResponseBody gets converted into Exceptions.
  */
-inline fun <reified T> HttpResponse.parseResultOrNull(): T? {
-    if (!status.success()) throw HttpException(status, status.name)
-    if (body.isNullOrBlank()) throw OcpiToolkitResponseParsingException("missing obligatory body in response")
+inline fun <reified T> HttpResponse.parseOcpiResponseBodyAndHandleErrors(
+    deserializeFn: (String?) -> OcpiResponseBody<T>,
+): T? {
+    if (!status.success()) {
+        // We know there was an error, so an exception must be thrown, we will try to throw an OcpiException if the
+        // error is formatted as an OCPI error
+        runCatching { deserializeFn(body) }
+            .getOrElse {
+                // If deserialization fails, it means that the response is probably not an OCPI error (if it is, it is
+                // incorrectly formatted, so we read it as a regular HttpException)
+                throw HttpException(status, status.name)
+            }
+            .throwOcpiException(status)
+    }
 
-    return runCatching { mapper.deserializeOcpiResponse<T>(body) }
-        .onFailure { e ->
+    // We know the message is a success, so it must be formatted as an OCPI response, so we can safely throw an
+    // exception if it is not the case
+    return runCatching { deserializeFn(body) }
+        .getOrElse { e ->
             throw OcpiToolkitResponseParsingException("Response cannot be parsed: $body", e)
         }
-        .getOrNull()
-        ?.also { it.maybeThrowOcpiException(status) }
-        ?.data
+        .also { parsedOcpiResponse ->
+            // who knows, maybe the partner responded with 200 or 201, but the OCPI payload is an error, in that case
+            // throw the error
+            if (!parsedOcpiResponse.statusCode.toOcpiStatus().isSuccess()) {
+                parsedOcpiResponse.throwOcpiException(status)
+            }
+        }
+        .data
 }
 
-inline fun <reified T> OcpiResponseBody<T>.maybeThrowOcpiException(httpStatus: HttpStatus = HttpStatus.OK) {
-    if (statusCode != OcpiStatus.SUCCESS.code) {
-        throw OcpiException(
-            httpStatus = httpStatus,
-            ocpiStatus = statusCode.toOcpiStatus(),
-            ocpiStatusCode = statusCode,
-            message = statusMessage ?: "",
-        )
-    }
+inline fun <reified T> OcpiResponseBody<T>.throwOcpiException(httpStatus: HttpStatus) {
+    throw OcpiException(
+        httpStatus = httpStatus,
+        ocpiStatus = statusCode.toOcpiStatus(),
+        ocpiStatusCode = statusCode,
+        message = statusMessage.orEmpty(),
+    )
 }

ocpi-toolkit-2.2.1/src/main/kotlin/com/izivia/ocpi/toolkit/common/OcpiStatus.kt

@@ -85,6 +85,9 @@ enum class OcpiStatus(val code: Int) {
      * Used when status code in response is unknown, most likely a custom code
      */
     UNKNOWN(9999),
+    ;
+
+    fun isSuccess(): Boolean = code in 1000..1999
 }
 
 fun Int.toOcpiStatus(): OcpiStatus = OcpiStatus.values().firstOrNull { it.code == this } ?: OcpiStatus.UNKNOWN