AI 生成: 基于 Flask 的 AI 免费对话应用，后端集成豆包（Doubao）和 DeepSeek，通过 SSE 实时推送消息，前端提供简洁的聊天界面。

static/css/style.css

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+* {
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0;
+}
+
+body {
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
+    "Microsoft YaHei", sans-serif;
+  background: #f5f6fa;
+  color: #1f2937;
+  height: 100vh;
+  overflow: hidden;
+}
+
+.app {
+  display: flex;
+  flex-direction: column;
+  height: 100vh;
+  max-width: 900px;
+  margin: 0 auto;
+  background: #fff;
+  box-shadow: 0 0 24px rgba(0, 0, 0, 0.06);
+}
+
+.header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 14px 20px;
+  border-bottom: 1px solid #e5e7eb;
+  background: linear-gradient(90deg, #6366f1, #8b5cf6);
+  color: #fff;
+}
+
+.header h1 {
+  font-size: 18px;
+  font-weight: 600;
+}
+
+.provider-switch {
+  display: flex;
+  gap: 12px;
+  font-size: 14px;
+}
+
+.provider-switch label {
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.chat {
+  flex: 1;
+  overflow-y: auto;
+  padding: 20px;
+  display: flex;
+  flex-direction: column;
+  gap: 14px;
+}
+
+.message {
+  display: flex;
+}
+
+.message.user {
+  justify-content: flex-end;
+}
+
+.bubble {
+  max-width: 78%;
+  padding: 10px 14px;
+  border-radius: 14px;
+  line-height: 1.6;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+  font-size: 15px;
+}
+
+.message.user .bubble {
+  background: #6366f1;
+  color: #fff;
+  border-bottom-right-radius: 4px;
+}
+
+.message.assistant .bubble {
+  background: #f1f3f8;
+  color: #1f2937;
+  border-bottom-left-radius: 4px;
+}
+
+.composer {
+  display: flex;
+  gap: 10px;
+  padding: 12px 16px;
+  border-top: 1px solid #e5e7eb;
+  background: #fafafa;
+}
+
+.composer textarea {
+  flex: 1;
+  resize: none;
+  height: 48px;
+  padding: 12px 14px;
+  border: 1px solid #d1d5db;
+  border-radius: 10px;
+  font-size: 15px;
+  font-family: inherit;
+  outline: none;
+  transition: border-color 0.2s;
+}
+
+.composer textarea:focus {
+  border-color: #6366f1;
+}
+
+.composer button {
+  padding: 0 22px;
+  border: none;
+  border-radius: 10px;
+  background: #6366f1;
+  color: #fff;
+  font-size: 15px;
+  font-weight: 600;
+  cursor: pointer;
+  transition: background 0.2s;
+}
+
+.composer button:hover {
+  background: #4f46e5;
+}
+
+.composer button:disabled {
+  background: #a5b4fc;
+  cursor: not-allowed;
+}
+
+.cursor::after {
+  content: "▋";
+  animation: blink 1s steps(2, start) infinite;
+  margin-left: 2px;
+  color: #6366f1;
+}
+
+@keyframes blink {
+  to {
+    visibility: hidden;
+  }
+}

static/js/main.js

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+// AI 免费对话 - 前端逻辑
+(function () {
+  const chatEl = document.getElementById("chat");
+  const inputEl = document.getElementById("input");
+  const sendBtn = document.getElementById("send");
+
+  // 保存对话历史（用于多轮上下文）
+  const history = [];
+  let sending = false;
+
+  /** 获取当前选择的 provider */
+  function getProvider() {
+    const el = document.querySelector('input[name="provider"]:checked');
+    return el ? el.value : "deepseek";
+  }
+
+  /** 追加一条消息到界面 */
+  function appendMessage(role, content) {
+    const wrapper = document.createElement("div");
+    wrapper.className = `message ${role}`;
+    const bubble = document.createElement("div");
+    bubble.className = "bubble";
+    bubble.textContent = content;
+    wrapper.appendChild(bubble);
+    chatEl.appendChild(wrapper);
+    chatEl.scrollTop = chatEl.scrollHeight;
+    return bubble;
+  }
+
+  /** 发送消息并接收 SSE 流 */
+  async function send() {
+    if (sending) return;
+    const text = inputEl.value.trim();
+    if (!text) return;
+
+    sending = true;
+    sendBtn.disabled = true;
+    inputEl.value = "";
+
+    // 展示用户消息
+    appendMessage("user", text);
+    history.push({ role: "user", content: text });
+
+    // 展示助手占位
+    const bubble = appendMessage("assistant", "");
+    bubble.classList.add("cursor");
+
+    let assistantText = "";
+
+    try {
+      const resp = await fetch("api/chat", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({
+          provider: getProvider(),
+          messages: history,
+        }),
+      });
+
+      if (!resp.ok || !resp.body) {
+        throw new Error("网络请求失败");
+      }
+
+      const reader = resp.body.getReader();
+      const decoder = new TextDecoder("utf-8");
+      let buffer = "";
+
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        buffer += decoder.decode(value, { stream: true });
+
+        // 按 SSE 事件分隔（\n\n）
+        const parts = buffer.split("\n\n");
+        buffer = parts.pop(); // 保留最后不完整片段
+
+        for (const part of parts) {
+          const line = part.trim();
+          if (!line.startsWith("data:")) continue;
+          const data = line.slice(5).trim();
+          if (data === "[DONE]") continue;
+          try {
+            const obj = JSON.parse(data);
+            if (obj.error) {
+              assistantText += `\n[错误] ${obj.error}`;
+              bubble.textContent = assistantText;
+            } else if (obj.content) {
+              assistantText += obj.content;
+              bubble.textContent = assistantText;
+              chatEl.scrollTop = chatEl.scrollHeight;
+            }
+          } catch (e) {
+            // 忽略解析错误
+          }
+        }
+      }
+    } catch (err) {
+      assistantText += `\n[错误] ${err.message}`;
+      bubble.textContent = assistantText;
+    } finally {
+      bubble.classList.remove("cursor");
+      if (assistantText) {
+        history.push({ role: "assistant", content: assistantText });
+      }
+      sending = false;
+      sendBtn.disabled = false;
+      inputEl.focus();
+    }
+  }
+
+  // 事件绑定
+  sendBtn.addEventListener("click", send);
+  inputEl.addEventListener("keydown", function (e) {
+    if (e.key === "Enter" && !e.shiftKey) {
+      e.preventDefault();
+      send();
+    }
+  });
+})();