Merge pull request #62 from amir1376/improve-download-engine-wrong-content-range-header-fix

some servers send wrong content-range headers now handled correctly

downloader/core/src/main/kotlin/ir/amirab/downloader/connection/response/ResponseInfo.kt

@@ -22,12 +22,16 @@ data class ResponseInfo(
         responseHeaders["content-length"]?.toLongOrNull()?.takeIf { it >= 0L }
     }
 
+    val contentRange by lazy {
+        getContentRange()
+    }
+
     //total length of whole file even if it is partial content
     val totalLength by lazy {
         val responseLength = contentLength ?: return@lazy null
         // partial length only valid when we have content-length header
         if (isPartial) {
-            getContentRange()?.fullSize
+            contentRange?.fullSize ?: responseLength
         } else responseLength
     }
     val requiresAuth by lazy {
@@ -43,8 +47,8 @@ data class ResponseInfo(
     }
 
     val resumeSupport by lazy {
-        // maybe server does not give us content-length, so we ignore resume support
-        isPartial && contentLength != null
+        // maybe server does not give us content-length or content-range, so we ignore resume support
+        isPartial && contentLength != null && contentRange?.fullSize!=null
     }
 
     val fileName: String? by lazy {

downloader/core/src/main/kotlin/ir/amirab/downloader/connection/response/headers/RangeHeaderExtractor.kt

@@ -7,37 +7,42 @@ data class ContentRangeValue(
     val fullSize: Long?,
 )
 
-fun ResponseInfo.getContentRange(): ContentRangeValue?{
-    val value=responseHeaders["content-range"]?:return null
-    val actualValue=runCatching {
+fun ResponseInfo.getContentRange(): ContentRangeValue? {
+    val value = responseHeaders["content-range"] ?: return null
+    val actualValue = runCatching {
         value.substring("bytes ".length)
-    }.getOrNull()?:return null
-    if (actualValue.isBlank()){
+    }.getOrNull() ?: return null
+    if (actualValue.isBlank()) {
         return null
     }
-    var from:Long?=null
-    var to:Long?=null
-    var size:Long?=null
-    val (rangeString,sizeString)=actualValue.split("/")
-    if (rangeString!="*"){
-        rangeString.split("-").map {
-            it.toLong()
-        }.let {
-            from=it[0]
-            to=it[1]
+
+    val (rangeString, sizeString) = actualValue
+        .split("/")
+        .takeIf { it.size >= 2 } ?: return null
+
+    val range = try {
+        if (rangeString != "*") {
+            rangeString.split("-").map {
+                it.toLong()
+            }.let {
+                it[0]..it[1]
+            }
+        } else {
+            null
         }
-    }
-    if (sizeString!="*"){
-        size=sizeString.toLong()
+    } catch (e: Exception) {
+        // NumberFormatException or IndexOutOfBoundException
+        return null
     }
 
+    val size: Long? = if (sizeString != "*") {
+        // some servers not returning * nor integer value.
+        sizeString.toLongOrNull() ?: return null
+    } else null
+
     return ContentRangeValue(
-        range = from?.let {f->
-            to?.let {t->
-                f..t
-            }
-        },
-        fullSize=size
+        range = range,
+        fullSize = size,
     )
 
 }