Refactor downloading routine

CMakeLists.txt

@@ -75,8 +75,8 @@ add_executable(streetview_client ${APPLICATION_TYPE}
 	src/main.cpp
 	src/parse.cpp
 	src/extract.cpp
-	src/equirectangular.cpp
 	src/renderer.cpp
+	src/download.cpp
 )
 
 set_target_properties(streetview_client PROPERTIES POSITION_INDEPENDENT_CODE ON)

src/download.cpp

@@ -0,0 +1,140 @@
+#include "download.hpp"
+
+#include <core/SkData.h>
+#include <core/SkImage.h>
+#include <fmt/format.h>
+
+#include <iostream>
+
+#include "extract.hpp"
+#include "headers.hpp"
+#include "parse.hpp"
+
+static size_t write_memory_callback(void* contents, size_t size, size_t nmemb, void* userp) {
+	size_t realsize = size * nmemb;
+	auto& mem       = *static_cast<std::string*>(userp);
+	mem.append(static_cast<char*>(contents), realsize);
+	return realsize;
+}
+
+std::string download_from_url(
+	std::string url, CURL* curl_handle, CURLcode* res, curl_slist* headers) {
+	std::string download;
+	curl_easy_setopt(curl_handle, CURLOPT_URL, url.c_str());
+	curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_memory_callback);
+	curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, &download);
+	if(headers) {
+		curl_easy_setopt(curl_handle, CURLOPT_HTTPHEADER, headers);
+	}
+
+	// added options that may be required
+	curl_easy_setopt(curl_handle, CURLOPT_FOLLOWLOCATION, 1L); // redirects
+	curl_easy_setopt(curl_handle, CURLOPT_HTTPPROXYTUNNEL,
+		1L);                                                   // corp. proxies etc.
+	// curl_easy_setopt(curl_handle, CURLOPT_VERBOSE, 1L); // we want it all
+	//  curl_easy_setopt(curl_handle, CURLOPT_REDIR_PROTOCOLS, CURLPROTO_HTTP |
+	//  CURLPROTO_HTTPS);
+
+	*res = curl_easy_perform(curl_handle);
+
+	if(*res != CURLE_OK) {
+		std::cerr << "Downloading failed: " << curl_easy_strerror(*res) << std::endl;
+	}
+
+	return download;
+}
+
+std::string download_client_id(CURL* curl_handle) {
+	CURLcode res;
+	auto main_page_download = download_from_url(
+		"https://www.google.com/maps", curl_handle, &res, get_main_page_headers());
+	auto client_id = parse_client_id(main_page_download);
+	return client_id;
+}
+
+rapidjson::Document download_preview_document(
+	CURL* curl_handle, std::string client_id, int num_previews, double lat, double lng, int range) {
+	CURLcode res;
+	auto photo_preview_download = download_from_url(
+		fmt::format("https://www.google.com/maps/preview/"
+					"photo?authuser=0&hl=en&gl=us&pb=!1e3!5m54!2m2!1i203!2i100!3m3!2i{}"
+					"!"
+					"3s{}!5b1!7m42!1m3!1e1!2b0!3e3!1m3!1e2!2b1!3e2!1m3!1e2!2b0!3e3!1m3!"
+					"1e8!"
+					"2b0!3e3!1m3!1e10!2b0!3e3!1m3!1e10!2b1!3e2!1m3!1e9!2b1!3e2!1m3!"
+					"1e10!"
+					"2b0!"
+					"3e3!1m3!1e10!2b1!3e2!1m3!1e10!2b0!3e4!2b1!4b1!8m0!9b0!11m1!4b1!"
+					"6m3!"
+					"1s{}"
+					"!"
+					"7e81!15i11021!9m2!2d{}!3d{}!10d{}",
+			num_previews, "CAEIBAgFCAYgAQ", client_id, lng, lat, range),
+		curl_handle, &res, NULL);
+
+	// Parse into JSON
+	rapidjson::Document preview_document;
+	preview_document.Parse(photo_preview_download.substr(4));
+
+	return preview_document;
+}
+
+rapidjson::Document download_photometa(
+	CURL* curl_handle, std::string client_id, std::string panorama_id) {
+	CURLcode res;
+	auto photometa_url = fmt::format("https://www.google.com/maps/photometa/"
+									 "v1?authuser=0&hl=en&gl=us&pb=!1m4!1smaps_sv.tactile!11m2!"
+									 "2m1!"
+									 "1b1!2m2!1sen!2sus!3m3!1m2!1e2!2s{}!4m57!1e1!1e2!1e3!1e4!1e5!"
+									 "1e6!1e8!1e12!2m1!1e1!4m1!1i48!5m1!1e1!5m1!1e2!6m1!1e1!6m1!"
+									 "1e2!"
+									 "9m36!1m3!1e2!2b1!3e2!1m3!1e2!2b0!3e3!1m3!1e3!2b1!3e2!1m3!"
+									 "1e3!"
+									 "2b0!3e3!1m3!1e8!2b0!3e3!1m3!1e1!2b0!3e3!1m3!1e4!2b0!3e3!1m3!"
+									 "1e10!2b1!3e2!1m3!1e10!2b0!3e3",
+		panorama_id);
+	auto photometa_download
+		= download_from_url(photometa_url, curl_handle, &res, get_photometa_headers());
+	rapidjson::Document photometa_document;
+	photometa_document.Parse(photometa_download.substr(4));
+
+	return photometa_document;
+}
+
+sk_sp<SkSurface> download_panorama(CURL* curl_handle, std::string panorama_id, int streetview_zoom,
+	rapidjson::Document& photmeta_document) {
+	auto [tiles_width, tiles_height] = extract_tiles_dimensions(photmeta_document, streetview_zoom);
+
+	sk_sp<SkSurface> tile_surface
+		= SkSurface::MakeRasterN32Premul(tiles_width * 512, tiles_height * 512);
+
+	// Start processing
+	tile_surface->getCanvas()->clear(SK_ColorWHITE);
+	for(int y = 0; y < tiles_height; y++) {
+		for(int x = 0; x < tiles_width; x++) {
+			// Download the specific tile
+			CURLcode res;
+			auto tile_url = fmt::format("https://streetviewpixels-pa.googleapis.com/v1/"
+										"tile?cb_client=maps_sv.tactile&panoid={}&x={}&"
+										"y={}&zoom={}&nbt=1&fover=2",
+				panorama_id, x, y, streetview_zoom);
+			auto tile_download
+				= download_from_url(tile_url, curl_handle, &res, get_panorama_headers());
+
+			if(res == CURLE_OK) {
+				long http_code = 0;
+				curl_easy_getinfo(curl_handle, CURLINFO_RESPONSE_CODE, &http_code);
+				if(http_code == 200) {
+					// Construct an image from the data
+					auto image = SkImage::MakeFromEncoded(
+						SkData::MakeWithoutCopy(tile_download.data(), tile_download.size()));
+					tile_surface->getCanvas()->drawImage(image, 512 * x, 512 * y);
+				} else {
+					std::cout << "Error code " << http_code << std::endl;
+				}
+			}
+		}
+	}
+
+	return tile_surface;
+}

src/download.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#define RAPIDJSON_HAS_STDSTRING 1
+
+#include <core/SkCanvas.h>
+#include <core/SkSurface.h>
+#include <curl/curl.h>
+#include <rapidjson/document.h>
+
+#include <string>
+
+std::string download_from_url(
+	std::string url, CURL* curl_handle, CURLcode* res, curl_slist* headers);
+std::string download_client_id(CURL* curl_handle);
+rapidjson::Document download_preview_document(
+	CURL* curl_handle, std::string client_id, int num_previews, double lat, double lng, int range);
+rapidjson::Document download_photometa(
+	CURL* curl_handle, std::string client_id, std::string panorama_id);
+sk_sp<SkSurface> download_panorama(CURL* curl_handle, std::string panorama_id, int streetview_zoom,
+	rapidjson::Document& photmeta_document);

src/extract.cpp

@@ -7,6 +7,37 @@
 
 #include <iostream>
 
+std::vector<std::string> extract_panorama_ids(rapidjson::Document& preview_document) {
+	std::vector<std::string> ids;
+	if(preview_document.IsArray() && preview_document.Size() == 11) {
+		if(preview_document[0].IsArray() && preview_document[0].Size() > 0) {
+			// std::cout << preview_document[0].Size() << " previews" << std::endl;
+			for(auto& preview : preview_document[0].GetArray()) {
+				if(preview.IsArray() && preview.Size() == 32) {
+					if(preview[0].IsString()) {
+						auto panorama_id
+							= std::string(preview[0].GetString(), preview[0].GetStringLength());
+						if(panorama_id.size() != 22) {
+							// Not a street view
+							continue;
+						}
+						ids.push_back(panorama_id);
+					} else {
+						std::cout << "Panorama id is not a string" << std::endl;
+					}
+				} else {
+					std::cout << "Panorama is not well formed" << std::endl;
+				}
+			}
+		} else {
+			std::cout << "No street view panoramas here" << std::endl;
+		}
+	} else {
+		std::cout << "Is not well formed array" << std::endl;
+	}
+	return ids;
+}
+
 Location extract_location(rapidjson::Document& photometa_document) {
 	Location location;
 	auto& outer_location = photometa_document[1][0][3];
@@ -46,4 +77,12 @@ std::vector<Panorama> extract_adjacent_panoramas(rapidjson::Document& photometa_
 		}
 	}
 	return panoramas;
+}
+
+std::pair<double, double> extract_tiles_dimensions(
+	rapidjson::Document& photometa_document, int streetview_zoom) {
+	auto& tiles_dimensions = photometa_document[1][0][2][2];
+	double tiles_width     = tiles_dimensions[1].GetInt() / 512 / pow(2, 5 - streetview_zoom);
+	double tiles_height    = tiles_dimensions[0].GetInt() / 512 / pow(2, 5 - streetview_zoom);
+	return std::make_pair(tiles_width, tiles_height);
 }

src/extract.hpp

@@ -3,6 +3,7 @@
 #include <rapidjson/document.h>
 
 #include <string>
+#include <utility>
 #include <vector>
 
 struct Location {
@@ -16,5 +17,8 @@ struct Panorama {
 	std::string id;
 };
 
+std::vector<std::string> extract_panorama_ids(rapidjson::Document& preview_document);
 Location extract_location(rapidjson::Document& photometa_document);
-std::vector<Panorama> extract_adjacent_panoramas(rapidjson::Document& photometa_document);
+std::vector<Panorama> extract_adjacent_panoramas(rapidjson::Document& photometa_document);
+std::pair<double, double> extract_tiles_dimensions(
+	rapidjson::Document& photometa_document, int streetview_zoom);