WebClient下载两张图片后处理

淩亂°似流年 2024-03-17 19:07 169阅读 0赞

函数需要做两件事情，根据请求vo里的url字段，下载2个图片。调用myService的方法，将结果填在返回vo里。使用Webflux的webclient  
三种方法的共同代码：

private void writeRecord(String logId, String f1Url, String f2Url, Float similarity) {
            IdentityEntity e = new IdentityEntity();
            e.setF1Url(f1Url);
            e.setF2Url(f2Url);
            e.setSimilarity(similarity);
            e.setLogId(logId);
            this.repository.save(e);
        }

方法一的共同代码：

private Mono<ClientResponse> getImage(String url) {
            return webClient.get()
                    .uri(url)
                    .exchange();
        }

方案一、下载图片1，如果成功，再下载图片2。都下载之后进行处理。

@Override
        public Mono<IdentityResponseVo> compare(Mono<IdentityRequestVo> vo) {
            return vo.flatMap(v -> {
                Mono<ClientResponse> r1 = getImage(v.getF1Url());
                Mono<IdentityResponseVo> map = r1.flatMap(clientResponse -> {
                    if (!clientResponse.statusCode().is2xxSuccessful()) {
                        return Mono.just(new IdentityResponseVo(ERR_DOWNLOAD, v.getLogId()));
                    } else {
                        Mono<ClientResponse> r2 = getImage(v.getF2Url());
                        Mono<IdentityResponseVo> map1 = r2.flatMap(clientResponse2 -> {
                            if (!clientResponse2.statusCode().is2xxSuccessful()) {
    
                                return Mono.just(new IdentityResponseVo(ERR_DOWNLOAD, v.getLogId()));
                            } else {
                                // Convert first image to base64
                                Mono<String> f1Base64Mono = r1.flatMap(response -> response.bodyToMono(byte[].class))
                                        .map(Base64::encodeAsString);
    
                                // Convert second image to base64
                                Mono<String> f2Base64Mono = r2.flatMap(response -> response.bodyToMono(byte[].class))
                                        .map(Base64::encodeAsString);
    
                                Mono<AiIdentity> aiIdentityMono = f1Base64Mono.flatMap(f1Base64 ->
                                        f2Base64Mono.map(f2Base64 -> myService.handle(f1Base64, f2Base64))
                                                .doOnNext(ret -> this.writeRecord(v.getLogId(), v.getF1Url(), v.getF2Url(), ret.getSimilarity())));
                                return aiIdentityMono.map(ret -> IdentityResponseVo.transform(ret, v.getLogId()));
                            }
                        });
                        return map1;
                    }
                });
                return map;
            });
        }

方案二、下载两个图片，如果都是2xx才会进行处理，否则返回错误：

@Override
        public Mono<IdentityResponseVo> compare2(Mono<IdentityRequestVo> vo) {
            return vo.flatMap(v -> {
                Mono<ClientResponse> r1 = getImage(v.getF1Url());
                Mono<ClientResponse> r2 = getImage(v.getF2Url());
                Mono<Boolean> both2xx = Mono.zip(r1.map(ClientResponse::statusCode), r2.map(ClientResponse::statusCode))
                        .map(statusCode -> {
                            log.info("{} is error: {} and {} is error: {}",
                                    v.getF1Url(), statusCode.getT1().is2xxSuccessful(),
                                    v.getF2Url(), statusCode.getT2().is2xxSuccessful());
                            return statusCode.getT1().is2xxSuccessful() && statusCode.getT2().is2xxSuccessful();
                        });
    
    
                return both2xx.flatMap(received -> {
                    if (received) {
                        // Convert first image to base64
                        Mono<String> f1Base64Mono = r1.flatMap(response -> response.bodyToMono(byte[].class))
                                .map(Base64::encodeAsString);
    
                        // Convert second image to base64
                        Mono<String> f2Base64Mono = r2.flatMap(response -> response.bodyToMono(byte[].class))
                                .map(Base64::encodeAsString);
    
                        Mono<AiIdentity> aiIdentityMono = f1Base64Mono.flatMap(f1Base64 ->
                                f2Base64Mono.map(f2Base64 -> myService.handle(f1Base64, f2Base64))
                        ).doOnNext(ret -> this.writeRecord(v.getLogId(), v.getF1Url(), v.getF2Url(), ret.getSimilarity()));
                        return aiIdentityMono.map(ret -> IdentityResponseVo.transform(ret, v.getLogId()));
                    } else {
                        // Return default JSON if any of the images were not received successfully
                        return Mono.just(new IdentityResponseVo(ERR_DOWNLOAD, v.getLogId()));
                    }
                });
            });
        }

方案三、“同时”下载图片1和2，通过onErrorReturn，处理任何一个图片响应不是2xx的情况  
如果下载图片响应不是404，会得到Mono.error， WebResponseException，这时onErrorReturn就会执行。如果响应404，Controller层直接返回，没有任何的body或者日志。那是因为Mono.empty，终止了整个数据流。

private Mono<String> getImageByUrl(String url) {
            Mono<byte[]> mono = webClient.get()
                    .uri(url)
                    .retrieve()
                    .bodyToMono(byte[].class)
                    .onErrorResume(WebClientResponseException.class,
                            ex -> ex.getRawStatusCode() == 404 ? Mono.empty() : Mono.error(ex));
            return mono.map(Base64::encodeAsString);
        }
    
        @Override
        public Mono<IdentityResponseVo> compare(Mono<IdentityRequestVo> vo) {
            return vo.flatMap(v -> {
                Mono<String> f1Base64Mono = getImageByUrl(v.getF1Url());
                Mono<String> f2Base64Mono = getImageByUrl(v.getF2Url());
                Mono<AiIdentity> aiIdentityMono = f1Base64Mono.flatMap(f1Base64 ->
                        f2Base64Mono.map(f2Base64 -> myService.handle(f1Base64, f2Base64))
                ).doOnNext(ret -> this.writeRecord(v.getLogId(), v.getF1Url(), v.getF2Url(), ret.getSimilarity()));
                return aiIdentityMono.map(ret -> IdentityResponseVo.transform(ret, v.getLogId()))
                        .onErrorReturn(new IdentityResponseVo(ResponseState.ERR_DOWNLOAD, v.getLogId()));
            });
        }