add DavCollection.post()

src/main/kotlin/at/bitfire/dav4jvm/DavCollection.kt

@@ -10,10 +10,10 @@ import at.bitfire.dav4jvm.XmlUtils.insertTag
 import at.bitfire.dav4jvm.exception.DavException
 import at.bitfire.dav4jvm.exception.HttpException
 import at.bitfire.dav4jvm.property.SyncToken
-import okhttp3.HttpUrl
-import okhttp3.OkHttpClient
-import okhttp3.Request
+import okhttp3.*
 import okhttp3.RequestBody.Companion.toRequestBody
+import okhttp3.Response
+import java.io.IOException
 import java.io.StringWriter
 import java.util.logging.Logger
 
@@ -33,6 +33,27 @@ open class DavCollection @JvmOverloads constructor(
         val NRESULTS = Property.Name(XmlUtils.NS_WEBDAV, "nresults")
     }
 
+    /**
+     * Sends a POST request. Primarily intended to be used with an Add-Member URL (RFC 5995).
+     */
+    @Throws(IOException::class, HttpException::class)
+    fun post(body: RequestBody, ifNoneMatch: Boolean = false, callback: (Response) -> Unit) {
+        followRedirects {
+            val builder = Request.Builder()
+                    .post(body)
+                    .url(location)
+
+            if (ifNoneMatch)
+                // don't overwrite anything existing
+                builder.header("If-None-Match", "*")
+
+            httpClient.newCall(builder.build()).execute()
+        }.use { response ->
+            checkStatus(response)
+            callback(response)
+        }
+    }
+
     /**
      * Sends a REPORT sync-collection request.
      *

src/main/kotlin/at/bitfire/dav4jvm/DavResource.kt

@@ -349,7 +349,7 @@ open class DavResource @JvmOverloads constructor(
      *
      * @throws HttpException in case of an HTTP error
      */
-    private fun checkStatus(response: Response) =
+    protected fun checkStatus(response: Response) =
             checkStatus(response.code, response.message, response)
 
     /**

src/test/kotlin/at/bitfire/dav4jvm/DavCollectionTest.kt

@@ -9,16 +9,21 @@ package at.bitfire.dav4jvm
 import at.bitfire.dav4jvm.exception.HttpException
 import at.bitfire.dav4jvm.property.GetETag
 import at.bitfire.dav4jvm.property.SyncToken
+import okhttp3.MediaType.Companion.toMediaType
 import okhttp3.OkHttpClient
+import okhttp3.RequestBody.Companion.toRequestBody
 import okhttp3.mockwebserver.MockResponse
 import okhttp3.mockwebserver.MockWebServer
 import org.junit.After
 import org.junit.Assert.*
 import org.junit.Before
 import org.junit.Test
+import java.net.HttpURLConnection
 
 class DavCollectionTest {
 
+    private val sampleText = "SAMPLE RESPONSE"
+
     private val httpClient = OkHttpClient.Builder()
             .followRedirects(false)
             .build()
@@ -223,4 +228,20 @@ class DavCollectionTest {
         }
     }
 
+    @Test
+    fun testPost() {
+        val url = sampleUrl()
+        val dav = DavCollection(httpClient, url)
+
+        // 201 Created
+        mockServer.enqueue(MockResponse().setResponseCode(HttpURLConnection.HTTP_CREATED))
+        var called = false
+        dav.post(sampleText.toRequestBody("text/plain".toMediaType())) { response ->
+            assertEquals("POST", mockServer.takeRequest().method)
+            assertEquals(response.request.url, dav.location)
+            called = true
+        }
+        assertTrue(called)
+    }
+
 }
\ No newline at end of file