update examples (#47)

examples/url-downloader/curl_adapter/src/main.rs

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2020 Fluence Labs Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use fluence::fce;
+use fluence::WasmLoggerBuilder;
+
+/// Log level can be changed by `RUST_LOG` env as well.
+pub fn main() {
+    WasmLoggerBuilder::new().build().unwrap();
+}
+
+#[fce]
+pub fn download(url: String) -> String {
+    log::info!("get called with url {}", url);
+
+    unsafe { curl(url) }
+}
+
+/// Permissions in `Config.toml` should exist to use host functions.
+#[fce]
+#[link(wasm_import_module = "host")]
+extern "C" {
+    fn curl(cmd: String) -> String;
+}