如何在 Angular RxJS

如何解决如何在 Angular RxJS

    this.route.params.pipe(
      concatMap((param) => {
        const ein = param['nonprofit-id'];
        return this.nonprofitService.getNonprofit(ein).pipe(
          concatMap((nonprofit) => {
            this.nonprofit = nonprofit;
            const ratingID = nonprofit.currentrating?.ratingID ? nonprofit.currentrating.ratingID : -1;
            return this.nonprofitService.getratingForNonprofit(ein,ratingID).pipe(
              concatMap((nonprofitrating) => {
                this.nonprofitrating = nonprofitrating;
                const causeID = this.nonprofit?.cause?.causeID ? this.nonprofit?.cause?.causeID : 0;
                return this.nonprofitService.getSimilarNonprofits(causeID);
              })
            );
          })
        );
      })
    ).subscribe((response) => {
      this.similarNonprofits = response;
    });

我想知道以上是否是在 Angular RxJS 中链接 concatMaps 的正确方法。另外两个调用依赖于正在检索的“非营利”，以便可以返回其对象。可以同时检索评级和类似非营利组织，所以我想有一些方法可以做到这一点，而无需将这些 concatMaps 相互嵌套。

解决方法

如果您需要使用所有以前的值，通常会以嵌套越来越多的链结束，但在这种情况下，它似乎已经太复杂了，因此您可以将每个内部 Observable const addActivityWithCountries = async(req,res) => { const activity = await Activity.create({ actId: req.body.actId,name: req.body.name,typeId: req.body.typeId,season: req.body.season,difficulty: req.body.difficulty,duration: req.body.duration,countries: req.body.countries },{ include: [Country] }).then((activity) => { res.json(activity) }).catch(err => console.log(err)) 放入一个数组（或对象）中，例如以下内容：

#include <WiFi.h>
#include <WiFiClientSecure.h>
#include "soc/soc.h"
#include "soc/rtc_cntl_reg.h"
#include "Base64.h"

#include "esp_camera.h"

const char* ssid     = "***";   //your network SSID
const char* password = "***";   //your network password
const char* myDomain = "script.google.com";
String myScript = "/macros/s/********/exec";    //Replace with your own url
String myFilename = "filename=ESP32-CAM.jpg";
String mimeType = "&mimetype=image/jpeg";
String myImage = "&data=";

int waitingTime = 30000; //Wait 30 seconds to google response.

#define PWDN_GPIO_NUM     32
#define RESET_GPIO_NUM    -1
#define XCLK_GPIO_NUM      0
#define SIOD_GPIO_NUM     26
#define SIOC_GPIO_NUM     27

#define Y9_GPIO_NUM       35
#define Y8_GPIO_NUM       34
#define Y7_GPIO_NUM       39
#define Y6_GPIO_NUM       36
#define Y5_GPIO_NUM       21
#define Y4_GPIO_NUM       19
#define Y3_GPIO_NUM       18
#define Y2_GPIO_NUM        5
#define VSYNC_GPIO_NUM    25
#define HREF_GPIO_NUM     23
#define PCLK_GPIO_NUM     22

void setup()
{
  WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG,0);
  
  Serial.begin(115200);
  delay(10);
  
  WiFi.mode(WIFI_STA);

  Serial.println("");
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid,password);  

  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }

  Serial.println("");
  Serial.println("STAIP address: ");
  Serial.println(WiFi.localIP());
    
  Serial.println("");

  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO_NUM;
  config.pin_d1 = Y3_GPIO_NUM;
  config.pin_d2 = Y4_GPIO_NUM;
  config.pin_d3 = Y5_GPIO_NUM;
  config.pin_d4 = Y6_GPIO_NUM;
  config.pin_d5 = Y7_GPIO_NUM;
  config.pin_d6 = Y8_GPIO_NUM;
  config.pin_d7 = Y9_GPIO_NUM;
  config.pin_xclk = XCLK_GPIO_NUM;
  config.pin_pclk = PCLK_GPIO_NUM;
  config.pin_vsync = VSYNC_GPIO_NUM;
  config.pin_href = HREF_GPIO_NUM;
  config.pin_sscb_sda = SIOD_GPIO_NUM;
  config.pin_sscb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn = PWDN_GPIO_NUM;
  config.pin_reset = RESET_GPIO_NUM;
  config.xclk_freq_hz = 20000000;
  config.pixel_format = PIXFORMAT_JPEG;
  

  if(psramFound()){
    config.frame_size = FRAMESIZE_UXGA; // FRAMESIZE_ + QVGA|CIF|VGA|SVGA|XGA|SXGA|UXGA
    config.jpeg_quality = 10; //10-63 lower number means higher quality
    config.fb_count = 2;
  } else {
    config.frame_size = FRAMESIZE_SVGA;
    config.jpeg_quality = 12;
    config.fb_count = 1;
  }

  
  
  esp_err_t err = esp_camera_init(&config);
  if (err != ESP_OK) {
    Serial.printf("Camera init failed with error 0x%x",err);
    delay(1000);
    ESP.restart();
  }
  sensor_t * s = esp_camera_sensor_get();
  s->set_brightness(s,0);     // -2 to 2
  s->set_contrast(s,0);       // -2 to 2
  s->set_saturation(s,0);     // -2 to 2
  s->set_special_effect(s,0); // 0 to 6 (0 - No Effect,1 - Negative,2 - Grayscale,3 - Red Tint,4 - Green Tint,5 - Blue Tint,6 - Sepia)
  s->set_whitebal(s,1);       // 0 = disable,1 = enable
  s->set_awb_gain(s,1 = enable
  s->set_wb_mode(s,0);        // 0 to 4 - if awb_gain enabled (0 - Auto,1 - Sunny,2 - Cloudy,3 - Office,4 - Home)
  s->set_exposure_ctrl(s,1);  // 0 = disable,1 = enable
  s->set_aec2(s,0);           // 0 = disable,1 = enable
  s->set_ae_level(s,0);       // -2 to 2
  s->set_aec_value(s,300);    // 0 to 1200
  s->set_gain_ctrl(s,1);      // 0 = disable,1 = enable
  s->set_agc_gain(s,0);       // 0 to 30
  s->set_gainceiling(s,(gainceiling_t)0);  // 0 to 6
  s->set_bpc(s,0);            // 0 = disable,1 = enable
  s->set_wpc(s,1);            // 0 = disable,1 = enable
  s->set_raw_gma(s,1);        // 0 = disable,1 = enable
  s->set_lenc(s,1);           // 0 = disable,1 = enable
  s->set_hmirror(s,0);        // 0 = disable,1 = enable
  s->set_vflip(s,0);          // 0 = disable,1 = enable
  s->set_dcw(s,1 = enable
  s->set_colorbar(s,0);       // 0 = disable,1 = enable
  s->set_framesize(s,FRAMESIZE_UXGA);
}

boolean enviar = true;

void loop() {
  //if(enviar) {
    saveCapturedImage();
    enviar = false;
    delay(60000);
  //}
}

void saveCapturedImage() {
  Serial.println("Connect to " + String(myDomain));
  WiFiClientSecure client;
  
  if (client.connect(myDomain,443)) {
    Serial.println("Connection successful");
    
    camera_fb_t * fb = NULL;
    fb = esp_camera_fb_get();  
    if(!fb) {
      Serial.println("Camera capture failed");
      delay(1000);
      ESP.restart();
      return;
    }
  
    char *input = (char *)fb->buf;
    char output[base64_enc_len(3)];
    String imageFile = "";
    for (int i=0;i<fb->len;i++) {
      base64_encode(output,(input++),3);
      if (i%3==0) imageFile += urlencode(String(output));
    }
    String Data = myFilename+mimeType+myImage;
    
    esp_camera_fb_return(fb);
    
    Serial.println("Send a captured image to Google Drive.");
    
    client.println("POST " + myScript + " HTTP/1.1");
    client.println("Host: " + String(myDomain));
    client.println("Content-Length: " + String(Data.length()+imageFile.length()));
    client.println("Content-Type: application/x-www-form-urlencoded");
    client.println();
    
    client.print(Data);
    int Index;
    for (Index = 0; Index < imageFile.length(); Index = Index+1000) {
      client.print(imageFile.substring(Index,Index+1000));
    }
    
    Serial.println("Waiting for response.");
    long int StartTime=millis();
    while (!client.available()) {
      Serial.print(".");
      delay(100);
      if ((StartTime+waitingTime) < millis()) {
        Serial.println();
        Serial.println("No response.");
        //If you have no response,maybe need a greater value of waitingTime
        break;
      }
    }
    Serial.println();   
    while (client.available()) {
      Serial.print(char(client.read()));
    }  
  } else {         
    Serial.println("Connected to " + String(myDomain) + " failed.");
  }
  client.stop();
}

//https://github.com/zenmanenergy/ESP8266-Arduino-Examples/
String urlencode(String str)
{
    String encodedString="";
    char c;
    char code0;
    char code1;
    char code2;
    for (int i =0; i < str.length(); i++){
      c=str.charAt(i);
      if (c == ' '){
        encodedString+= '+';
      } else if (isalnum(c)){
        encodedString+=c;
      } else{
        code1=(c & 0xf)+'0';
        if ((c & 0xf) >9){
            code1=(c & 0xf) - 10 + 'A';
        }
        c=(c>>4)&0xf;
        code0=c+'0';
        if (c > 9){
            code0=c - 10 + 'A';
        }
        code2='\0';
        encodedString+='%';
        encodedString+=code0;
        encodedString+=code1;
        //encodedString+=code2;
      }
      yield();
    }
    return encodedString;
}

显然，您不必解开作为参数传递给连续 map() 的每个数组，但我希望您明白这一点。

,

继续@martin 的回答，我建议使用 forkJoin 将最后两个 concatMap 组合到一个请求中，因为它们不相互依赖。这也将并行触发请求，并可能有助于提高性能（尽管微乎其微）。

我还用 nullish coalescing operator ?? 替换了三元运算符。

this.route.params.pipe(
  concatMap((param: any) => {
    const ein = param['nonprofit-id'];
    return this.nonprofitService.getNonprofit(ein).pipe(
      map((nonprofit) => ([ein,nonprofit]))
    );
  }),concatMap(([ein,nonprofit]) => 
    forkJoin([
      this.nonprofitService.getRatingForNonprofit(ein,(nonprofit.currentRating?.ratingID ?? -1)),this.nonprofitService.getSimilarNonprofits(ein,(this.nonprofit?.cause?.causeID ?? 0))
    ]).pipe(
      map(([nonprofitRating,similarNonprofits]) => ([
        nonprofit,nonprofitRating,similarNonprofits
      ]))
    )
  )
).subscribe({
  next: ([nonprofit,similarNonprofits]) => {
    this.nonprofit = nonprofit;
    this.nonprofitRating = nonprofitRating;
    this.similarNonprofits = similarNonprofits;
  },error: (error: any) => {
    // handle error
  }
});

您还可以定义具有属性的对象，以避免对多个元素使用解构语法。