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diff --git a/2025/07/29/nestjs-nested-object-dto/index.html b/2025/07/29/nestjs-nested-object-dto/index.html index 3e7695e5..b67e6ef3 100644 --- a/2025/07/29/nestjs-nested-object-dto/index.html +++ b/2025/07/29/nestjs-nested-object-dto/index.html @@ -193,40 +193,50 @@ </div> <div class="post-content"> <p>在开发 NestJS 应用程序时，一个常见的场景是根据复杂的条件筛选资源。当使用嵌套查询参数来表达这些条件时，例如通过 URL <code>http://localhost:3000/products/filter?filters[price][min]=100</code>，可能会意外地遇到 <code>property filters[price][min] should not exist</code> 错误。本文将深入剖析此问题背后的原因，并提供针对 Express 和 Fastify 两种底层框架的解决方案。</p> -<h4 id="问题背景"><a href="#问题背景" class="headerlink" title="问题背景"></a>问题背景</h4><p>假设我们正在构建一个电子商务平台的后端，需要实现一个商品筛选接口 <code>/products/filter</code>。该接口应允许客户端根据不同的属性（如价格 <code>price</code>、库存 <code>stock</code>）进行筛选，并支持对数值型属性（如价格）指定一个范围。</p> +<h4 id="问题背景"><a class="header-anchor" href="#问题背景">¶</a>问题背景</h4> +<p>假设我们正在构建一个电子商务平台的后端，需要实现一个商品筛选接口 <code>/products/filter</code>。该接口应允许客户端根据不同的属性（如价格 <code>price</code>、库存 <code>stock</code>）进行筛选，并支持对数值型属性（如价格）指定一个范围。</p> <p>为了实现这一功能，我们定义了以下 NestJS 数据传输对象 (DTO) 结构：</p> <figure class="highlight typescript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { <span class="title class_">ApiPropertyOptional</span> } <span class="keyword">from</span> <span class="string">"@nestjs/swagger"</span>;</span><br><span class="line"><span class="keyword">import</span> {</span><br><span class="line"> <span class="title class_">IsNumber</span>,</span><br><span class="line"> <span class="title class_">IsOptional</span>,</span><br><span class="line"> <span class="title class_">Min</span>,</span><br><span class="line"> <span class="title class_">ValidateNested</span>,</span><br><span class="line">} <span class="keyword">from</span> <span class="string">"class-validator"</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">Type</span> } <span class="keyword">from</span> <span class="string">"class-transformer"</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">class</span> <span class="title class_">RangeFilterDto</span> {</span><br><span class="line"> <span class="meta">@ApiPropertyOptional</span>({ <span class="attr">description</span>: <span class="string">"最小值 (大于等于)"</span> })</span><br><span class="line"> <span class="meta">@IsOptional</span>()</span><br><span class="line"> <span class="meta">@Type</span>(<span class="function">() =></span> <span class="title class_">Number</span>)</span><br><span class="line"> <span class="meta">@IsNumber</span>()</span><br><span class="line"> <span class="meta">@Min</span>(<span class="number">0</span>)</span><br><span class="line"> <span class="attr">min</span>?: <span class="built_in">number</span>;</span><br><span class="line"></span><br><span class="line"> <span class="meta">@ApiPropertyOptional</span>({ <span class="attr">description</span>: <span class="string">"最大值 (小于等于)"</span> })</span><br><span class="line"> <span class="meta">@IsOptional</span>()</span><br><span class="line"> <span class="meta">@Type</span>(<span class="function">() =></span> <span class="title class_">Number</span>)</span><br><span class="line"> <span class="meta">@IsNumber</span>()</span><br><span class="line"> <span class="meta">@Min</span>(<span class="number">0</span>)</span><br><span class="line"> <span class="attr">max</span>?: <span class="built_in">number</span>;</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">class</span> <span class="title class_">ProductAttributeFilterDto</span> {</span><br><span class="line"> <span class="meta">@ApiPropertyOptional</span>({</span><br><span class="line"> <span class="attr">description</span>: <span class="string">"价格范围"</span>,</span><br><span class="line"> <span class="attr">type</span>: <span class="title class_">RangeFilterDto</span>,</span><br><span class="line"> })</span><br><span class="line"> <span class="meta">@IsOptional</span>()</span><br><span class="line"> <span class="meta">@ValidateNested</span>()</span><br><span class="line"> <span class="meta">@Type</span>(<span class="function">() =></span> <span class="title class_">RangeFilterDto</span>)</span><br><span class="line"> <span class="attr">price</span>?: <span class="title class_">RangeFilterDto</span>;</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">export</span> <span class="keyword">class</span> <span class="title class_">ProductFilterDto</span> {</span><br><span class="line"> <span class="meta">@ApiPropertyOptional</span>({ <span class="attr">description</span>: <span class="string">"商品属性筛选条件"</span> })</span><br><span class="line"> <span class="meta">@IsOptional</span>()</span><br><span class="line"> <span class="meta">@ValidateNested</span>()</span><br><span class="line"> <span class="meta">@Type</span>(<span class="function">() =></span> <span class="title class_">ProductAttributeFilterDto</span>)</span><br><span class="line"> <span class="attr">filters</span>?: <span class="title class_">ProductAttributeFilterDto</span>;</span><br><span class="line">}</span><br></pre></td></tr></table></figure> - <p>对应的控制器代码如下：</p> <figure class="highlight typescript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { <span class="title class_">Controller</span>, <span class="title class_">Get</span>, <span class="title class_">Query</span> } <span class="keyword">from</span> <span class="string">'@nestjs/common'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">ApiOperation</span>, <span class="title class_">ApiResponse</span>, <span class="title class_">ApiTags</span> } <span class="keyword">from</span> <span class="string">'@nestjs/swagger'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">ProductFilterDto</span> } <span class="keyword">from</span> <span class="string">'./dtos/product-filter.dto'</span>;</span><br><span class="line"></span><br><span class="line"><span class="meta">@ApiTags</span>(<span class="string">'products'</span>)</span><br><span class="line"><span class="meta">@Controller</span>(<span class="string">'products'</span>)</span><br><span class="line"><span class="keyword">export</span> <span class="keyword">class</span> <span class="title class_">ProductsController</span> {</span><br><span class="line"> <span class="meta">@Get</span>(<span class="string">"filter"</span>)</span><br><span class="line"> <span class="meta">@ApiOperation</span>({ <span class="attr">summary</span>: <span class="string">"根据条件筛选商品"</span> })</span><br><span class="line"> <span class="meta">@ApiResponse</span>({ <span class="attr">status</span>: <span class="number">200</span>, <span class="attr">description</span>: <span class="string">"筛选商品成功"</span> })</span><br><span class="line"> <span class="meta">@ApiResponse</span>({ <span class="attr">status</span>: <span class="number">400</span>, <span class="attr">description</span>: <span class="string">"请求参数错误"</span> })</span><br><span class="line"> <span class="keyword">async</span> <span class="title function_">getFilteredProducts</span>(</span><br><span class="line"> <span class="meta">@Query</span>() <span class="attr">query</span>: <span class="title class_">ProductFilterDto</span>,</span><br><span class="line"> ): <span class="title class_">Promise</span><<span class="built_in">any</span>> {</span><br><span class="line"> <span class="comment">// 在实际应用中，这里会调用服务处理筛选逻辑</span></span><br><span class="line"> <span class="variable language_">console</span>.<span class="title function_">log</span>(query);</span><br><span class="line"> <span class="keyword">return</span> {</span><br><span class="line"> <span class="attr">message</span>: <span class="string">"Products filtered successfully."</span>,</span><br><span class="line"> <span class="attr">data</span>: query,</span><br><span class="line"> };</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure> - <p>当客户端通过以下 URL 发送请求时：</p> <p><code>http://localhost:3000/products/filter?filters[price][min]=100</code></p> <p>后端返回了 HTTP 400 错误，并附带以下日志：</p> <figure class="highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">[Nest] 12345 - 07/29/2025, 11:00:00 AM ERROR [HttpExceptionFilter] [GET /products/filter?filters%5Bprice%5D%5Bmin%5D=100] HTTP 400 Error: property filters[price][min] should not exist</span><br><span class="line">BadRequestException: Bad Request Exception</span><br><span class="line"> at ValidationPipe.exceptionFactory (/path/to/project/node_modules/@nestjs/common/pipes/validation.pipe.js:107:20)</span><br><span class="line"> at ValidationPipe.transform (/path/to/project/node_modules/@nestjs/common/pipes/validation.pipe.js:74:30)</span><br><span class="line"> ... (其他堆栈信息)</span><br></pre></td></tr></table></figure> - -<h4 id="错误分析"><a href="#错误分析" class="headerlink" title="错误分析"></a>错误分析</h4><p>此错误的核心在于 NestJS 的 <code>@Query()</code> 装饰器与 <code>ValidationPipe</code> 在处理 URL 查询字符串时的默认行为，未能正确地将客户端提供的嵌套方括号语法 (<code>filters[price][min]</code>) 解析为 DTO 所期望的 JavaScript 嵌套对象结构。</p> +<h4 id="错误分析"><a class="header-anchor" href="#错误分析">¶</a>错误分析</h4> +<p>此错误的核心在于 NestJS 的 <code>@Query()</code> 装饰器与 <code>ValidationPipe</code> 在处理 URL 查询字符串时的默认行为，未能正确地将客户端提供的嵌套方括号语法 (<code>filters[price][min]</code>) 解析为 DTO 所期望的 JavaScript 嵌套对象结构。</p> <ol> -<li><p><strong>DTO 的预期结构:</strong><br><code>ProductFilterDto</code> 定义了 <code>filters</code> 属性，其类型为 <code>ProductAttributeFilterDto</code>。<code>ProductAttributeFilterDto</code> 又包含了 <code>price</code> 属性，类型为 <code>RangeFilterDto</code>，最终含有 <code>min</code> 和 <code>max</code> 属性。这意味着 DTO 期望接收的数据结构应为：<code>{ filters: { price: { min: 100 } } }</code>。</p> +<li> +<p><strong>DTO 的预期结构:</strong><br> +<code>ProductFilterDto</code> 定义了 <code>filters</code> 属性，其类型为 <code>ProductAttributeFilterDto</code>。<code>ProductAttributeFilterDto</code> 又包含了 <code>price</code> 属性，类型为 <code>RangeFilterDto</code>，最终含有 <code>min</code> 和 <code>max</code> 属性。这意味着 DTO 期望接收的数据结构应为：<code>{ filters: { price: { min: 100 } } }</code>。</p> </li> -<li><p><strong>URL 查询参数的扁平化解析:</strong><br>HTTP 协议的查询字符串本质上是扁平的键值对集合。虽然 <code>key[nestedKey]=value</code> 这种方括号语法被许多 Web 框架（如 PHP、Ruby on Rails）和库（如 <code>qs</code>）广泛用于表示嵌套数据，但这并非 HTTP 协议的标准。<br>NestJS 依赖其底层 HTTP 适配器（默认为 Express）来解析传入的请求。在默认配置下，Express 不会自动地、递归地将 <code>filters[price][min]</code> 这样的字符串键名解析成一个具有正确嵌套层级的 JavaScript 对象。相反，它会将其视为一个完整的、扁平的字符串键名 <code>filters[price][min]</code>，并将其值 <code>100</code> 与之对应。</p> +<li> +<p><strong>URL 查询参数的扁平化解析:</strong><br> +HTTP 协议的查询字符串本质上是扁平的键值对集合。虽然 <code>key[nestedKey]=value</code> 这种方括号语法被许多 Web 框架（如 PHP、Ruby on Rails）和库（如 <code>qs</code>）广泛用于表示嵌套数据，但这并非 HTTP 协议的标准。<br> +NestJS 依赖其底层 HTTP 适配器（默认为 Express）来解析传入的请求。在默认配置下，Express 不会自动地、递归地将 <code>filters[price][min]</code> 这样的字符串键名解析成一个具有正确嵌套层级的 JavaScript 对象。相反，它会将其视为一个完整的、扁平的字符串键名 <code>filters[price][min]</code>，并将其值 <code>100</code> 与之对应。</p> </li> -<li><p><strong><code>ValidationPipe</code> 的验证失败:</strong><br>当 <code>ValidationPipe</code> 接收到被扁平化解析后的查询参数时，它会在 <code>ProductFilterDto</code> 中寻找一个名为 <code>filters[price][min]</code> 的顶层属性。由于 DTO 中并未直接定义这样一个扁平的属性，并且 <code>ValidationPipe</code> 通常会启用 <code>forbidNonWhitelisted: true</code> 或 <code>whitelist: true</code> 选项来拒绝 DTO 中未明确声明的属性，因此验证过程失败，并抛出 <code>property filters[price][min] should not exist</code> 的错误。这表明 <code>ValidationPipe</code> 将 <code>filters[price][min]</code> 视为一个非法的、未在白名单中的属性，而不是预期的嵌套对象 <code>filters</code> 下的深层子属性。</p> +<li> +<p><strong><code>ValidationPipe</code> 的验证失败:</strong><br> +当 <code>ValidationPipe</code> 接收到被扁平化解析后的查询参数时，它会在 <code>ProductFilterDto</code> 中寻找一个名为 <code>filters[price][min]</code> 的顶层属性。由于 DTO 中并未直接定义这样一个扁平的属性，并且 <code>ValidationPipe</code> 通常会启用 <code>forbidNonWhitelisted: true</code> 或 <code>whitelist: true</code> 选项来拒绝 DTO 中未明确声明的属性，因此验证过程失败，并抛出 <code>property filters[price][min] should not exist</code> 的错误。这表明 <code>ValidationPipe</code> 将 <code>filters[price][min]</code> 视为一个非法的、未在白名单中的属性，而不是预期的嵌套对象 <code>filters</code> 下的深层子属性。</p> </li> </ol> <p>简而言之，问题不在于 DTO 定义或 <code>@Query()</code> 装饰器本身，而在于底层 HTTP 框架对查询字符串的默认解析行为与 NestJS <code>ValidationPipe</code> 对复杂嵌套 DTO 结构的需求不匹配。</p> -<h4 id="解决方案"><a href="#解决方案" class="headerlink" title="解决方案"></a>解决方案</h4><p>要解决此问题，关键在于配置 NestJS 应用的底层 HTTP 适配器，使其能够正确地解析包含方括号语法的嵌套查询参数，将其转换为嵌套的 JavaScript 对象。</p> -<h5 id="针对-Express-适配器"><a href="#针对-Express-适配器" class="headerlink" title="针对 Express 适配器"></a>针对 Express 适配器</h5><p>如果您的 NestJS 应用使用 Express 作为底层 HTTP 框架（这是新项目的默认配置），您需要在应用的入口文件（通常是 <code>main.ts</code>）中，通过 <code>app.set('query parser', 'extended');</code> 显式启用 Express 的扩展查询字符串解析功能。此配置会指示 Express 使用 <code>qs</code> 库（Express 内置依赖）来处理查询字符串，该库能够正确处理嵌套结构。</p> +<h4 id="解决方案"><a class="header-anchor" href="#解决方案">¶</a>解决方案</h4> +<p>要解决此问题，关键在于配置 NestJS 应用的底层 HTTP 适配器，使其能够正确地解析包含方括号语法的嵌套查询参数，将其转换为嵌套的 JavaScript 对象。</p> +<h5 id="针对-Express-适配器"><a class="header-anchor" href="#针对-Express-适配器">¶</a>针对 Express 适配器</h5> +<p>如果您的 NestJS 应用使用 Express 作为底层 HTTP 框架（这是新项目的默认配置），您需要在应用的入口文件（通常是 <code>main.ts</code>）中，通过 <code>app.set('query parser', 'extended');</code> 显式启用 Express 的扩展查询字符串解析功能。此配置会指示 Express 使用 <code>qs</code> 库（Express 内置依赖）来处理查询字符串，该库能够正确处理嵌套结构。</p> <p>示例 (<code>main.ts</code>):</p> <figure class="highlight typescript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { <span class="title class_">NestFactory</span> } <span class="keyword">from</span> <span class="string">'@nestjs/core'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">AppModule</span> } <span class="keyword">from</span> <span class="string">'./app.module'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">ValidationPipe</span> } <span class="keyword">from</span> <span class="string">'@nestjs/common'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">NestExpressApplication</span> } <span class="keyword">from</span> <span class="string">'@nestjs/platform-express'</span>; <span class="comment">// 导入此类型</span></span><br><span class="line"></span><br><span class="line"><span class="keyword">async</span> <span class="keyword">function</span> <span class="title function_">bootstrap</span>(<span class="params"></span>) {</span><br><span class="line"> <span class="keyword">const</span> app = <span class="keyword">await</span> <span class="title class_">NestFactory</span>.<span class="property">create</span><<span class="title class_">NestExpressApplication</span>>(<span class="title class_">AppModule</span>);</span><br><span class="line"></span><br><span class="line"> <span class="comment">// 启用 Express 的扩展查询参数解析</span></span><br><span class="line"> <span class="comment">// 'simple' (默认) | 'extended'</span></span><br><span class="line"> app.<span class="title function_">set</span>(<span class="string">'query parser'</span>, <span class="string">'extended'</span>);</span><br><span class="line"></span><br><span class="line"> app.<span class="title function_">useGlobalPipes</span>(<span class="keyword">new</span> <span class="title class_">ValidationPipe</span>({</span><br><span class="line"> <span class="attr">whitelist</span>: <span class="literal">true</span>, <span class="comment">// 自动剥离 DTO 中未定义的属性</span></span><br><span class="line"> <span class="attr">forbidNonWhitelisted</span>: <span class="literal">true</span>, <span class="comment">// 如果传入 DTO 中未定义的属性，则抛出错误</span></span><br><span class="line"> <span class="attr">transform</span>: <span class="literal">true</span>, <span class="comment">// 自动将负载转换为 DTO 类的实例</span></span><br><span class="line"> <span class="attr">transformOptions</span>: {</span><br><span class="line"> <span class="attr">enableImplicitConversion</span>: <span class="literal">true</span>, <span class="comment">// 允许隐式类型转换，配合 @Type()</span></span><br><span class="line"> },</span><br><span class="line"> }));</span><br><span class="line"></span><br><span class="line"> <span class="comment">// ... 其他配置</span></span><br><span class="line"> <span class="keyword">await</span> app.<span class="title function_">listen</span>(<span class="number">3000</span>);</span><br><span class="line">}</span><br><span class="line"><span class="title function_">bootstrap</span>();</span><br></pre></td></tr></table></figure> - -<h5 id="针对-Fastify-适配器"><a href="#针对-Fastify-适配器" class="headerlink" title="针对 Fastify 适配器"></a>针对 Fastify 适配器</h5><p>如果您的 NestJS 应用使用 Fastify 作为底层 HTTP 框架，您需要在创建 Fastify 适配器实例时，通过 <code>querystringParser</code> 选项提供一个自定义的查询字符串解析函数。通常，我们会利用 <code>qs</code> 这样的成熟库来完成递归解析。</p> -<p>首先，确保已安装 <code>qs</code> 库及其类型定义：<br><code>npm install qs</code><br><code>npm install -D @types/qs</code></p> +<h5 id="针对-Fastify-适配器"><a class="header-anchor" href="#针对-Fastify-适配器">¶</a>针对 Fastify 适配器</h5> +<p>如果您的 NestJS 应用使用 Fastify 作为底层 HTTP 框架，您需要在创建 Fastify 适配器实例时，通过 <code>querystringParser</code> 选项提供一个自定义的查询字符串解析函数。通常，我们会利用 <code>qs</code> 这样的成熟库来完成递归解析。</p> +<p>首先，确保已安装 <code>qs</code> 库及其类型定义：<br> +<code>npm install qs</code><br> +<code>npm install -D @types/qs</code></p> <p>示例 (<code>main.ts</code>):</p> <figure class="highlight typescript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { <span class="title class_">NestFactory</span> } <span class="keyword">from</span> <span class="string">'@nestjs/core'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">AppModule</span> } <span class="keyword">from</span> <span class="string">'./app.module'</span>;</span><br><span class="line"><span class="keyword">import</span> { <span class="title class_">ValidationPipe</span> } <span class="keyword">from</span> <span class="string">'@nestjs/common'</span>;</span><br><span class="line"><span class="keyword">import</span> {</span><br><span class="line"> <span class="title class_">FastifyAdapter</span>,</span><br><span class="line"> <span class="title class_">NestFastifyApplication</span>,</span><br><span class="line">} <span class="keyword">from</span> <span class="string">'@nestjs/platform-fastify'</span>;</span><br><span class="line"><span class="keyword">import</span> * <span class="keyword">as</span> qs <span class="keyword">from</span> <span class="string">'qs'</span>; <span class="comment">// 引入 qs 库</span></span><br><span class="line"></span><br><span class="line"><span class="keyword">async</span> <span class="keyword">function</span> <span class="title function_">bootstrap</span>(<span class="params"></span>) {</span><br><span class="line"> <span class="keyword">const</span> app = <span class="keyword">await</span> <span class="title class_">NestFactory</span>.<span class="property">create</span><<span class="title class_">NestFastifyApplication</span>>(</span><br><span class="line"> <span class="title class_">AppModule</span>,</span><br><span class="line"> <span class="keyword">new</span> <span class="title class_">FastifyAdapter</span>({</span><br><span class="line"> <span class="comment">// 配置 Fastify 的查询字符串解析器</span></span><br><span class="line"> <span class="attr">querystringParser</span>: <span class="function">(<span class="params">str</span>) =></span> qs.<span class="title function_">parse</span>(str),</span><br><span class="line"> }),</span><br><span class="line"> );</span><br><span class="line"></span><br><span class="line"> app.<span class="title function_">useGlobalPipes</span>(<span class="keyword">new</span> <span class="title class_">ValidationPipe</span>({</span><br><span class="line"> <span class="attr">whitelist</span>: <span class="literal">true</span>,</span><br><span class="line"> <span class="attr">forbidNonWhitelisted</span>: <span class="literal">true</span>,</span><br><span class="line"> <span class="attr">transform</span>: <span class="literal">true</span>,</span><br><span class="line"> <span class="attr">transformOptions</span>: {</span><br><span class="line"> <span class="attr">enableImplicitConversion</span>: <span class="literal">true</span>,</span><br><span class="line"> },</span><br><span class="line"> }));</span><br><span class="line"></span><br><span class="line"> <span class="comment">// ... 其他配置</span></span><br><span class="line"> <span class="keyword">await</span> app.<span class="title function_">listen</span>(<span class="number">3000</span>);</span><br><span class="line">}</span><br><span class="line"><span class="title function_">bootstrap</span>();</span><br></pre></td></tr></table></figure> - -<p>通过上述配置，无论是使用 Express 还是 Fastify，NestJS 应用都将能够正确地将 <code>?filters[price][min]=100</code> 解析为 <code>{ filters: { price: { min: '100' } } }</code>。随后，在 <code>ValidationPipe</code> 的 <code>transform</code> 阶段，<code>@Type(() => Number)</code> 装饰器会确保 <code>min</code> 的值从字符串 <code>'100'</code> 转换为数字 <code>100</code>，从而顺利通过验证并注入到控制器方法中。</p> -<h3 id="引用"><a href="#引用" class="headerlink" title="引用"></a>引用</h3><ul> +<p>通过上述配置，无论是使用 Express 还是 Fastify，NestJS 应用都将能够正确地将 <code>?filters[price][min]=100</code> 解析为 <code>{ filters: { price: { min: '100' } } }</code>。随后，在 <code>ValidationPipe</code> 的 <code>transform</code> 阶段，<code>@Type(() => Number)</code> 装饰器会确保 <code>min</code> 的值从字符串 <code>'100'</code> 转换为数字 <code>100</code>，从而顺利通过验证并注入到控制器方法中。</p> +<h3 id="引用"><a class="header-anchor" href="#引用">¶</a>引用</h3> +<ul> <li><a target="_blank" rel="noopener" href="https://stackoverflow.com/questions/29960764/what-does-extended-mean-in-express-4-0">What does ‘extended’ mean in express 4.0? - Stack Overflow</a></li> <li><a target="_blank" rel="noopener" href="https://expressjs.com/en/5x/api.html#app.set">Express 5.0 - API Reference (<code>app.set</code>)</a></li> </ul> |