{"record":{"id":"52573c5bb3c812d0","repo":"Yalantis/uCrop","slug":"cimg-load-network-failed-to-load-file-s-wit","errorCode":null,"errorMessage":"cimg::load_network(): Failed to load file '%s' with libcurl.","messagePattern":"cimg::load_network\\(\\): Failed to load file '(.+?)' with libcurl\\.","errorType":"exception","errorClass":"CImgIOException","httpStatus":null,"severity":"error","filePath":"ucrop/src/main/jni/CImg.h","lineNumber":70108,"sourceCode":"          curl_easy_setopt(curl,CURLOPT_SSL_VERIFYHOST,0L);\n          curl_easy_setopt(curl,CURLOPT_FOLLOWLOCATION,1L);\n          curl_easy_setopt(curl,CURLOPT_MAXREDIRS,20L);\n          if (timeout) curl_easy_setopt(curl,CURLOPT_TIMEOUT,(long)timeout);\n          if (std::strchr(url,'?')) curl_easy_setopt(curl,CURLOPT_HTTPGET,1L);\n          if (referer) curl_easy_setopt(curl,CURLOPT_REFERER,referer);\n          if (user_agent) curl_easy_setopt(curl,CURLOPT_USERAGENT,user_agent);\n          res = curl_easy_perform(curl);\n          curl_easy_cleanup(curl);\n          cimg::fseek(file,0,SEEK_END); // Check if file size is 0\n          const cimg_ulong siz = cimg::ftell(file);\n          cimg::fclose(file);\n          file = 0;\n          if (siz>0 && res==CURLE_OK) { cimg::exception_mode(omode); return filename_local; }\n          else std::remove(filename_local);\n        }\n      } catch (...) { }\n      cimg::exception_mode(omode);\n      if (!try_fallback) throw CImgIOException(\"cimg::load_network(): Failed to load file '%s' with libcurl.\",url);\n#endif\n\n      CImg<char> command((unsigned int)std::strlen(url) + 1024), s_referer, s_user_agent, s_timeout;\n      cimg::unused(try_fallback);\n\n      // Try with 'curl' first.\n      if (timeout) cimg_snprintf(s_timeout.assign(64),64,\"-m %u \",timeout);\n      else s_timeout.assign(1,1,1,1,0);\n      if (referer) cimg_snprintf(s_referer.assign(1024),1024,\"-e %s \",referer);\n      else s_referer.assign(1,1,1,1,0);\n      if (user_agent) cimg_snprintf(s_user_agent.assign(1024),1024,\"-A \\\"%s\\\" \",user_agent);\n      else s_user_agent.assign(1,1,1,1,0);\n      cimg_snprintf(command,command._width,\n                    \"\\\"%s\\\" -L --max-redirs 20 %s%s%s-f --silent --compressed -o \\\"%s\\\" \\\"%s\\\"\",\n                    cimg::curl_path(),s_timeout._data,s_referer._data,s_user_agent._data,filename_local,\n                    CImg<char>::string(url)._system_strescape().data());\n      cimg::system(command,cimg::curl_path());\n","sourceCodeStart":70090,"sourceCodeEnd":70126,"githubUrl":"https://github.com/Yalantis/uCrop/blob/f788b534b48c144edf786c8cddbf0e029e637804/ucrop/src/main/jni/CImg.h#L70090-L70126","documentation":"After the libcurl attempt in cimg::load_network() fails (curl not available, DNS failure, HTTP error, timeout, or empty/partial download) and fallback is not allowed, the library throws this CImgIOException reporting that the URL could not be downloaded with libcurl. It wraps any underlying curl error into a single user-visible failure.","triggerScenarios":"load_network(url, local, timeout, try_fallback=false, ...) where libcurl returned an error (CURLE_* failure, HTTP >= 400, zero-byte response) — thrown only when try_fallback is false, i.e. wget/curl binary fallback is skipped.","commonSituations":"Server or CDN returning 404/403/5xx for a remote image; device offline or DNS broken; TLS certificate problems on Android; timeout too small; URL wrong or expired (signed URLs).","solutions":["Verify the URL is reachable (browser/curl) and returns 200; fix expired or malformed URLs.","Enable fallback (try_fallback=true) so CImg can retry with the wget/curl binaries.","Increase the timeout parameter and check device network connectivity/permissions (INTERNET permission on Android).","Catch CImgIOException, log the URL, and fall back to a cached or bundled copy of the resource."],"exampleFix":"// before\nimg.load_network(url, local, 5, false, 0, 0); // throws on any curl failure\n// after\ntry {\n  img.load_network(url, local, 30, true, 0, 0);\n} catch (CImgIOException &e) {\n  fprintf(stderr, \"download failed, using cached copy: %s\", e.what());\n  img.load(\"cache/last_good.png\");\n}","handlingStrategy":"fallback","validationCode":"// pre-check reachability\nbool reachable = (system((std::string(\"curl -s -o /dev/null -w %{http_code} \") + url).c_str()) == 0);","typeGuard":null,"tryCatchPattern":"try { img.load_network(url, local, 30, true, 0, 0); } catch (const CImgIOException &e) { fprintf(stderr, \"download failed: %s\", e.what()); img.load(\"cache/last_good.png\"); }","preventionTips":["Use a generous timeout and try_fallback=true so wget/curl binaries can retry","Validate URLs return HTTP 200 and handle signed-URL expiry","Check connectivity and INTERNET permissions before attempting downloads on mobile","Keep a cached copy of previously downloaded resources for offline/error fallback"],"tags":["network","http","download-failed","cimg"],"backgroundTag":"network-request-failed","analyzedSha":"f788b534b48c144edf786c8cddbf0e029e637804","analyzedAt":"2026-09-08T08:36:04.887Z","contentChangedAt":"2026-09-08T08:36:04.887Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}