2 files changed, 203 insertions, 0 deletions
diff --git a/src/main/java/io/github/jshipit/DockerAPIHelper.java b/src/main/java/io/github/jshipit/DockerAPIHelper.java
new file mode 100755
index 0000000..dca582e
--- /dev/null
+++ b/src/main/java/io/github/jshipit/DockerAPIHelper.java
@@ -0,0 +1,162 @@
+package io.github.jshipit;
+
+
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+
+import java.io.*;
+import java.net.*;
+import java.util.Scanner;
+
+public class DockerAPIHelper {
+
+    private String apiToken;
+    private String apiRepo;
+    private String authURL;
+    private String repository;
+    private String image;
+
+    private String tag;
+
+    public DockerAPIHelper(String apiRepo, String authURL, String repository, String image, String tag) {
+        System.out.println("DockerAPIHelper constructor");
+        this.apiRepo = apiRepo;
+        this.repository = repository;
+        this.authURL = authURL;
+        this.image = image;
+        this.tag = tag;
+        try {
+            apiToken = generateAPIToken();
+        } catch (IOException | RuntimeException e) {
+            System.out.println("IOException | RuntimeException");
+            e.printStackTrace();
+        }
+    }
+
+    public String generateAPIToken() throws IOException, RuntimeException {
+        URL url_obj = null;
+        try {
+            url_obj = new URI(this.authURL + "?scope=repository:" + this.repository + "/" + this.image + ":pull"  + "&service=" + this.apiRepo).toURL();
+            System.out.println(url_obj.toString());
+        } catch (URISyntaxException | MalformedURLException e) {
+            System.out.println("URISyntaxException | MalformedURLException");
+            e.printStackTrace();
+        }
+
+
+        assert url_obj != null;
+        HttpURLConnection con = (HttpURLConnection) url_obj.openConnection();
+        con.setRequestMethod("GET");
+        con.connect();
+        if (con.getResponseCode() != 200) {
+            System.out.println("Error: " + con.getResponseCode());
+            throw new RuntimeException("Failed : HTTP error code : "
+                    + con.getResponseCode());
+        } else {
+            System.out.println("Success: " + con.getResponseCode());
+            String output = "";
+            Scanner scanner = new Scanner(url_obj.openStream());
+            while (scanner.hasNext()) {
+                output += scanner.nextLine();
+            }
+            scanner.close();
+            System.out.println(output);
+            ObjectMapper mapper = new ObjectMapper();
+            JsonNode token = mapper.readTree(output);
+            System.out.println(token.get("token").asText());
+            return token.get("token").asText();
+        }
+    }
+
+    public JsonNode fetchManifestJson() throws IOException, RuntimeException {
+        URL url_obj = null;
+        try {
+            String repo = this.apiRepo.replace("registry", "registry-1");
+            url_obj = new URI("https://" + repo + "/v2/" + this.repository + "/" + this.image + "/manifests/"+this.tag).toURL();
+            System.out.println(url_obj.toString());
+        } catch(URISyntaxException | MalformedURLException e) {
+            System.out.println("URISyntaxException | MalformedURLException");
+            e.printStackTrace();
+        }
+
+        assert url_obj != null;
+        HttpURLConnection con = (HttpURLConnection) url_obj.openConnection();
+        con.setRequestMethod("GET");
+        con.setRequestProperty("Authorization", "Bearer " + this.apiToken);
+        con.setRequestProperty("Accept", "application/vnd.docker.distribution.manifest.v2+json");
+        con.connect();
+
+        if (con.getResponseCode() != 200) {
+            System.out.println("Error: " + con.getResponseCode());
+            throw new RuntimeException("Failed : HTTP error code : "
+                    + con.getResponseCode());
+        } else {
+            System.out.println("Success: " + con.getResponseCode());
+            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
+            String inputLine;
+            StringBuffer content = new StringBuffer();
+            while ((inputLine = in.readLine()) != null) {
+                content.append(inputLine);
+            }
+            in.close();
+            con.disconnect();
+            ObjectMapper mapper = new ObjectMapper();
+            JsonNode manifest = mapper.readTree(content.toString());
+            return manifest;
+        }
+    }
+
+    public void fetchBlob(String digest, String tmpdir) throws IOException, RuntimeException {
+        URL url_obj = null;
+        try {
+            String repo = this.apiRepo.replace("registry", "registry-1");
+            url_obj = new URI("https://" + repo + "/v2/" + this.repository + "/" + this.image + "/blobs/"+digest).toURL();
+            System.out.println(url_obj.toString());
+        } catch(URISyntaxException | MalformedURLException e) {
+            System.out.println("URISyntaxException | MalformedURLException");
+            e.printStackTrace();
+        }
+
+        assert url_obj != null;
+        HttpURLConnection con = (HttpURLConnection) url_obj.openConnection();
+        con.setRequestMethod("GET");
+        con.setRequestProperty("Authorization", "Bearer " + this.apiToken);
+        con.setRequestProperty("Accept", "application/vnd.docker.distribution.manifest.v2+json");
+        con.connect();
+
+        if (con.getResponseCode() != 200) {
+            System.out.println("Error: " + con.getResponseCode());
+            throw new RuntimeException("Failed : HTTP error code : "
+                    + con.getResponseCode());
+        } else {
+            System.out.println("Success: " + con.getResponseCode());
+        }
+        // Stream file download and output progress
+        InputStream inputStream = con.getInputStream();
+        FileOutputStream outputStream = new FileOutputStream(tmpdir+"/"+digest.replace("sha256:", "")+"layer.tar");
+
+        byte[] buffer = new byte[1024];
+        int bytesRead;
+        while ((bytesRead = inputStream.read(buffer)) != -1) {
+            outputStream.write(buffer, 0, bytesRead);
+        }
+
+        outputStream.close();
+        inputStream.close();
+        System.out.println("File downloaded successfully.");
+    }
+
+    public String getApiToken() {
+        return apiToken;
+    }
+
+    public String getImage() {
+        return image;
+    }
+
+    public String getTag() {
+        return tag;
+    }
+}
diff --git a/src/main/java/io/github/jshipit/Main.java b/src/main/java/io/github/jshipit/Main.java
new file mode 100755
index 0000000..df1cea7
--- /dev/null
+++ b/src/main/java/io/github/jshipit/Main.java
@@ -0,0 +1,41 @@
+package io.github.jshipit;
+
+import com.fasterxml.jackson.databind.JsonNode;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class Main {
+    public static void main(String[] args) {
+        DockerAPIHelper api = new DockerAPIHelper("registry.docker.io", "https://auth.docker.io/token", "library", "archlinux", "latest");
+        JsonNode manifest = null;
+
+        System.out.println("API Token: " + api.getApiToken());
+        try {
+            manifest = api.fetchManifestJson();
+        } catch (IOException e) {
+
+        }
+
+        System.out.println("Manifest: " + manifest);
+
+        Path path = Path.of("./tmp_"+api.getImage()+"_"+api.getTag());
+        try {
+            Files.createDirectory(path);
+        } catch (IOException e) {
+            System.out.println("Failed to create directory: " + path);
+            return;
+        }
+
+        JsonNode layers = manifest.get("layers");
+        for (JsonNode layer : layers) {
+            System.out.println("Layer: " + layer);
+            try {
+                api.fetchBlob(layer.get("digest").asText(), path.toString());
+            } catch (IOException e) {
+
+            }
+        }
+    }
+}
+\ No newline at end of file