feat: V4 POST policy

google-cloud-storage/src/main/java/com/google/cloud/storage/PostPolicyV4.java

@@ -0,0 +1,389 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * 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.
+ */
+
+package com.google.cloud.storage;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+import java.text.SimpleDateFormat;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Presigned V4 post policy.
+ *
+ * @see <a href="https://cloud.google.com/storage/docs/xml-api/post-object">POST Object</a>
+ */
+public final class PostPolicyV4 {
+  private String url;
+  private Map<String, String> fields;
+
+  private PostPolicyV4(String url, Map<String, String> fields) {
+    this.url = url;
+    this.fields = fields;
+  }
+
+  public static PostPolicyV4 of(String url, Map<String, String> fields) {
+    return new PostPolicyV4(url, fields);
+  }
+
+  public String getUrl() {
+    return url;
+  }
+
+  public Map<String, String> getFields() {
+    return fields;
+  }
+
+  /**
+   * Class representing which fields to specify in a V4 POST request.
+   *
+   * @see <a href="https://cloud.google.com/storage/docs/xml-api/post-object#form_fields">POST
+   *     Object Form fields</a>
+   */
+  public static final class PostFieldsV4 {
+    private Map<String, String> fieldsMap;
+
+    private PostFieldsV4(Builder builder) {
+      this.fieldsMap = builder.fieldsMap;
+    }
+
+    private PostFieldsV4(Map<String, String> fields) {
+      this.fieldsMap = fields;
+    }
+
+    public static PostFieldsV4 of(Map<String, String> fields) {
+      return new PostFieldsV4(fields);
+    }
+
+    public static Builder newBuilder() {
+      return new Builder();
+    }
+
+    public Map<String, String> getFieldsMap() {
+      return fieldsMap;
+    }
+
+    public static class Builder {
+      private Map<String, String> fieldsMap;
+
+      private Builder() {
+        fieldsMap = new HashMap<>();
+      }
+
+      public PostFieldsV4 build() {
+        return new PostFieldsV4(this);
+      }
+
+      public Builder setAcl(String acl) {
+        fieldsMap.put("acl", acl);
+        return this;
+      }
+
+      public Builder setCacheControl(String cacheControl) {
+        fieldsMap.put("cache-control", cacheControl);
+        return this;
+      }
+
+      public Builder setContentDisposition(String contentDisposition) {
+        fieldsMap.put("content-disposition", contentDisposition);
+        return this;
+      }
+
+      public Builder setContentEncoding(String contentEncoding) {
+        fieldsMap.put("content-encoding", contentEncoding);
+        return this;
+      }
+
+      public Builder setContentLength(int contentLength) {
+        fieldsMap.put("content-length", "" + contentLength);
+        return this;
+      }
+
+      public Builder setContentType(String contentType) {
+        fieldsMap.put("content-type", contentType);
+        return this;
+      }
+
+      public Builder Expires(String expires) {
+        fieldsMap.put("expires", expires);
+        return this;
+      }
+
+      public Builder setSuccessActionRedirect(String successActionRedirect) {
+        fieldsMap.put("success_action_redirect", successActionRedirect);
+        return this;
+      }
+
+      public Builder setSuccessActionStatus(int successActionStatus) {
+        fieldsMap.put("success_action_status", "" + successActionStatus);
+        return this;
+      }
+
+      public Builder AddCustomMetadataField(String field, String value) {
+        fieldsMap.put("x-goog-meta-" + field, value);
+        return this;
+      }
+    }
+  }
+
+  /**
+   * Class for specifying conditions in a V4 POST Policy document.
+   *
+   * @see <a href="https://cloud.google.com/storage/docs/authentication/signatures#policy-document">
+   *     Policy document</a>
+   */
+  public static final class PostConditionsV4 {
+    private Set<ConditionV4> conditions;
+
+    private static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
+
+    public PostConditionsV4(Builder builder) {
+      this.conditions = builder.conditions;
+    }
+
+    public Builder toBuilder() {
+      return new Builder(conditions);
+    }
+
+    public static Builder newBuilder() {
+      return new Builder();
+    }
+
+    public Set<ConditionV4> getConditions() {
+      return conditions;
+    }
+
+    public static class Builder {
+      Set<ConditionV4> conditions;
+
+      private Builder() {
+        this.conditions = new LinkedHashSet<>();
+      }
+
+      private Builder(Set<ConditionV4> conditions) {
+        this.conditions = conditions;
+      }
+
+      public static Builder newBuilder() {
+        return new Builder();
+      }
+
+      public PostConditionsV4 build() {
+        return new PostConditionsV4(this);
+      }
+
+      public Builder addAclCondition(ConditionV4Type type, String acl) {
+        conditions.add(new ConditionV4(type, "acl", acl));
+        return this;
+      }
+
+      public Builder addBucketCondition(ConditionV4Type type, String bucket) {
+        conditions.add(new ConditionV4(type, "bucket", bucket));
+        return this;
+      }
+
+      public Builder addCacheControlCondition(ConditionV4Type type, String cacheControl) {
+        conditions.add(new ConditionV4(type, "cache-control", cacheControl));
+        return this;
+      }
+
+      public Builder addContentDispositionCondition(
+          ConditionV4Type type, String contentDisposition) {
+        conditions.add(new ConditionV4(type, "content-disposition", contentDisposition));
+        return this;
+      }
+
+      public Builder addContentEncodingCondition(ConditionV4Type type, String contentEncoding) {
+        conditions.add(new ConditionV4(type, "content-encoding", contentEncoding));
+        return this;
+      }
+
+      public Builder addContentLengthCondition(ConditionV4Type type, int contentLength) {
+        conditions.add(new ConditionV4(type, "content-length", "" + contentLength));
+        return this;
+      }
+
+      public Builder addContentTypeCondition(ConditionV4Type type, String contentType) {
+        conditions.add(new ConditionV4(type, "content-type", contentType));
+        return this;
+      }
+
+      public Builder addExpiresCondition(ConditionV4Type type, long expires) {
+        conditions.add(new ConditionV4(type, "expires", dateFormat.format(expires)));
+        return this;
+      }
+
+      public Builder addExpiresCondition(ConditionV4Type type, String expires) {
+        conditions.add(new ConditionV4(type, "expires", expires));
+        return this;
+      }
+
+      public Builder addKeyCondition(ConditionV4Type type, String key) {
+        conditions.add(new ConditionV4(type, "key", key));
+        return this;
+      }
+
+      public Builder addSuccessActionRedirectUrlCondition(
+          ConditionV4Type type, String successActionRedirectUrl) {
+        conditions.add(new ConditionV4(type, "success_action_redirect", successActionRedirectUrl));
+        return this;
+      }
+
+      public Builder addSuccessActionStatusCondition(ConditionV4Type type, int status) {
+        conditions.add(new ConditionV4(type, "success_action_status", "" + status));
+        return this;
+      }
+
+      public Builder addContentLengthRangeCondition(int min, int max) {
+        conditions.add(new ConditionV4(ConditionV4Type.CONTENT_LENGTH_RANGE, "" + min, "" + max));
+        return this;
+      }
+
+      Builder addCustomCondition(ConditionV4Type type, String field, String value) {
+        conditions.add(new ConditionV4(type, field, value));
+        return this;
+      }
+    }
+  }
+
+  /**
+   * Class for a V4 POST Policy document.
+   *
+   * @see <a href="https://cloud.google.com/storage/docs/authentication/signatures#policy-document">
+   *     Policy document</a>
+   */
+  public static final class PostPolicyV4Document {
+    private String expiration;
+    private PostConditionsV4 conditions;
+
+    private PostPolicyV4Document(String expiration, PostConditionsV4 conditions) {
+      this.expiration = expiration;
+      this.conditions = conditions;
+    }
+
+    public static PostPolicyV4Document of(String expiration, PostConditionsV4 conditions) {
+      return new PostPolicyV4Document(expiration, conditions);
+    }
+
+    public String toJson() {
+      JsonObject object = new JsonObject();
+      JsonArray conditions = new JsonArray();
+      for (ConditionV4 condition : this.conditions.conditions) {
+        switch (condition.type) {
+          case MATCHES:
+            JsonObject match = new JsonObject();
+            match.addProperty(condition.operand1, condition.operand2);
+            conditions.add(match);
+            break;
+          case STARTS_WITH:
+            JsonArray startsWith = new JsonArray();
+            startsWith.add("starts-with");
+            startsWith.add("$" + condition.operand1);
+            startsWith.add(condition.operand2);
+            conditions.add(startsWith);
+            break;
+          case CONTENT_LENGTH_RANGE:
+            JsonArray contentLengthRange = new JsonArray();
+            contentLengthRange.add("content-length-range");
+            contentLengthRange.add(Integer.parseInt(condition.operand1));
+            contentLengthRange.add(Integer.parseInt(condition.operand2));
+            conditions.add(contentLengthRange);
+            break;
+        }
+      }
+      object.add("conditions", conditions);
+      object.addProperty("expiration", expiration);
+
+      String json = object.toString();
+      StringBuilder escapedJson = new StringBuilder();
+
+      // Certain characters in a policy must be escaped
+      for (char c : json.toCharArray()) {
+        if (c >= 128) { // is a unicode character
+          escapedJson.append(String.format("\\u%04x", (int) c));
+        } else {
+          switch (c) {
+            case '\\':
+              escapedJson.append("\\\\");
+              break;
+            case '\b':
+              escapedJson.append("\\b");
+              break;
+            case '\f':
+              escapedJson.append("\\f");
+              break;
+            case '\n':
+              escapedJson.append("\\n");
+              break;
+            case '\r':
+              escapedJson.append("\\r");
+              break;
+            case '\t':
+              escapedJson.append("\\t");
+              break;
+            case '\u000b':
+              escapedJson.append("\\v");
+              break;
+            default:
+              escapedJson.append(c);
+          }
+        }
+      }
+      return escapedJson.toString();
+    }
+  }
+
+  public enum ConditionV4Type {
+    MATCHES,
+    STARTS_WITH,
+    CONTENT_LENGTH_RANGE
+  }
+
+  /**
+   * Class for a specific POST policy document condition.
+   *
+   * @see <a href="https://cloud.google.com/storage/docs/authentication/signatures#policy-document">
+   *     Policy document</a>
+   */
+  static final class ConditionV4 {
+    ConditionV4Type type;
+    String operand1;
+    String operand2;
+
+    private ConditionV4(ConditionV4Type type, String operand1, String operand2) {
+      this.type = type;
+      this.operand1 = operand1;
+      this.operand2 = operand2;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      ConditionV4 condition = (ConditionV4) other;
+      return this.type == condition.type
+          && this.operand1.equals(condition.operand1)
+          && this.operand2.equals(condition.operand2);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(type, operand1, operand2);
+    }
+  }
+}