Add validation on Event serialization

2 files changed, 68 insertions, 6 deletions

diff --git a/include/nostr.hpp b/include/nostr.hpp
index 47b56f9..ec8d1a8 100644
--- a/include/nostr.hpp
+++ b/include/nostr.hpp
@@ -27,14 +27,32 @@ struct Event
 {
     std::string id; ///< SHA-256 hash of the event data.
     std::string pubkey; ///< Public key of the event creator.
-    std::string created_at; ///< Unix timestamp of the event creation.
+    std::time_t createdAt; ///< Unix timestamp of the event creation.
     int kind; ///< Event kind.
     std::vector<std::vector<std::string>> tags; ///< Arbitrary event metadata.
     std::string content; ///< Event content.
     std::string sig; ///< Event signature created with the private key of the event creator.
 
-    nlohmann::json serialize() const;
+    /**
+     * @brief Serializes the event to a JSON object.
+     * @returns A stringified JSON object representing the event.
+     * @throws `std::invalid_argument` if the event object is invalid.
+     */
+    std::string serialize();
+
+    /**
+     * @brief Deserializes the event from a JSON string.
+     * @param jsonString A stringified JSON object representing the event.
+     */
     void deserialize(std::string jsonString);
+
+private:
+    /**
+     * @brief Validates the event.
+     * @throws `std::invalid_argument` if the event object is invalid.
+     * @remark The `createdAt` field defaults to the present if it is not already set.
+     */
+    void validate();
 };
 
 class NostrService
diff --git a/src/event.cpp b/src/event.cpp
index 0e4e159..6a179fa 100644
--- a/src/event.cpp
+++ b/src/event.cpp
@@ -1,20 +1,31 @@
+#include <ctime>
 #include <string>
-#include <vector>
 #include <nlohmann/json.hpp>
 
 #include "nostr.hpp"
 
 using nlohmann::json;
+using std::invalid_argument;
 using std::string;
+using std::time;
 
 namespace nostr 
 {
-json Event::serialize() const
+string Event::serialize()
 {
+    try
+    {
+        this->validate();
+    }
+    catch (const invalid_argument& e)
+    {
+        throw e;
+    }
+
     json j = {
         {"id", this->id},
         {"pubkey", this->pubkey},
-        {"created_at", this->created_at},
+        {"created_at", this->createdAt},
         {"kind", this->kind},
         {"tags", this->tags},
         {"content", this->content},
@@ -28,10 +39,43 @@ void Event::deserialize(string jsonString)
     json j = json::parse(jsonString);
     this->id = j["id"];
     this->pubkey = j["pubkey"];
-    this->created_at = j["created_at"];
+    this->createdAt = j["created_at"];
     this->kind = j["kind"];
     this->tags = j["tags"];
     this->content = j["content"];
     this->sig = j["sig"];
 };
+
+void Event::validate()
+{
+    bool hasId = this->id.length() > 0;
+    if (!hasId)
+    {
+        throw std::invalid_argument("Event::validate: The event id is required.");
+    }
+
+    bool hasPubkey = this->pubkey.length() > 0;
+    if (!hasPubkey)
+    {
+        throw std::invalid_argument("Event::validate: The pubkey of the event author is required.");
+    }
+
+    bool hasCreatedAt = this->createdAt > 0;
+    if (!hasCreatedAt)
+    {
+        this->createdAt = time(nullptr);
+    }
+
+    bool hasKind = this->kind >= 0 && this->kind < 40000;
+    if (!hasKind)
+    {
+        throw std::invalid_argument("Event::validate: A valid event kind is required.");
+    }
+
+    bool hasSig = this->sig.length() > 0;
+    if (!hasSig)
+    {
+        throw std::invalid_argument("Event::validate: The event must be signed.");
+    }
+};
 } // namespace nostr